Genetically engineered vaccinia viruses

ABSTRACT

The present invention provides a genetically recombinant vaccinia virus effective in preventing or treating cancer. Specifically, the present invention provides a recombinant vaccinia virus lacking functions of VGF and O1L and having a gene encoding B5R in which an SCR domain has been deleted. Specifically, the present invention provides a vaccinia virus comprising two polynucleotides, a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12; a combination kit of two vaccinia viruses, a vaccinia virus comprising a polynucleotide encoding IL-7 and a vaccinia virus comprising a polynucleotide encoding IL-12; and use of the two vaccinia viruses in combination.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No. 15/664,125, filed Jul. 31, 2017, which is a continuation of International PCT Application No. PCT/JP2017/019921, filed May 29, 2017, which claims priority to Japanese Application No. JP 2016-107481, filed May 30, 2016, the entire contents of which are incorporated by reference in their entireties.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Feb. 27, 2019, is named PAS-5001US-01_CIP_Sequence_Listing.txt and is 159 kilobytes in size FIELD OF THE INVENTION

The present invention relates to genetically engineered vaccinia viruses.

BACKGROUND OF THE INVENTION

Various techniques for using viruses for cancer treatments have been recently developed. Vaccinia virus is one of the viruses used for cancer treatment. Vaccinia virus has been studied for cancer treatment as a vector for delivering therapeutic genes to cancer cells, as an oncolytic virus that proliferates in cancer cells and destroys the cancer cells, or as a cancer vaccine that expresses tumor antigens or immunomodulatory molecules (Guse et al. (2011) Expert Opinion on Biological Therapy 11: 595-608).

Vaccinia viruses engineered to have an N1L gene inactivated by the insertion of a foreign gene encoding interleukin-12 (IL-12) or interleukin-21 (IL-21) and to be deficient in the thymidine kinase (TK) gene by the insertion of the lacZ reporter gene and the firefly luciferase gene have been reported to suppress the tumor growth or improve the survival rate in cancer-bearing mice (PCT Patent Pub. No. WO2015/150809).

A technique for employing, for cancer treatment, recombinant vaccinia viruses that are deficient in the function of the viral proteins vaccinia virus growth factor (VGF) and O1L and proliferate specifically in cancer cells and destroy the cancer cells has been reported. Although it is stated that a foreign gene such as a marker gene or a therapeutic gene encoding a product having cytotoxicity or the immunopotentiating effect may be introduced into a gene that is not essential to the life cycle of vaccinia virus, the introduction of a gene specifically examined in Examples is that of a marker gene, a luciferase-green fluorescent protein (GFP) fusion gene or an expression cassette of DsRed. No therapeutic gene is examined for the introduction. No suggestion is made for combining plural therapeutic genes (PCT Patent Pub. No. WO2015/076422).

Meanwhile, it has been reported that, in the examination of effects of recombinant proteins on isolated CD8+ T cells, a recombinant human interleukin-7 (IL-7) protein alone does not induce detectable levels of interferon-gamma (IFN-γ) production by CD8+ T cells, but a combination of the recombinant human IL-7 protein and a recombinant human IL-12 protein synergistically enhances the production of IFN-γ (Mehrotra et al. (1995) The Journal of Immunology 154: 5093-5102). It has been reported that an oncolytic vaccinia virus that expresses an immune-stimulating molecule may rapidly be cleared by strong immune responses. It is also stated that strong immune response could serve either as a foe or as an ally to the vaccinia virus-mediated cancer therapy (Shen et al. (2005) Molecular Therapy 11(2): 180-195).

A technique has been reported in which a recombinant vaccinia virus lacking functions of vaccinia virus growth factor (VGF) as virus protein and O1L and specifically growing in cancer cells to destroy the cancer cells is used for cancer treatment (PCT Patent Pub. No. WO2015/076422). It is stated that as an attenuated vaccinia virus strain, a strain may be used in which a B5R gene has been partially or completely deleted, but it is also stated that expression of a complete B5R gene is desirable because cancer cells are injured under the action of B5R protein.

It has been reported that a WR strain (W-B5RΔSCR 1-4) and an IHD-J strain (I-B5RΔSCR 1-4) in which a part of an SCR (short consensus repeat) 1-4 domain (i.e. a part of SCR4 domain exclusive of 12 amino acids on the cytoplasm side) in the B5R extracellular region form a large plaque. Further, it is stated that regarding W-B5RΔSCR 1-4, infectious viruses were present in the supernatant in an amount that is maximum 10 times larger as compared to the wild type WR strain, and therefore promotion of release of an extracellular enveloped virus (EEV) is suggested (Herrera et al. (1998) Journal of Virology 72(1): 294-302). In contrast, it has been reported that the plaque phenotype of W-B5RΔSCR 1-4 is smaller than the wild type (Gray et al. (2002) Journal of General Virology 83: 323-333).

It has been reported that EEVs of W-B5RΔSCR 1-4 and I-B5RΔSCR 1-4 are more resistant to neutralization with anti-vaccinia virus serum than EEVs of wild types of these strains, respectively (Bell et al. (2004) Virology 325: 425-431).

With a view to providing a safer variola vaccine by creating a vaccine strain that hardly undergoes reversion (atavism), a variola vaccine has been reported which is consist of a vaccinia virus in which a part or the whole of a B5R gene of a vaccinia virus strain LC16 strain, LC16m8 strain or LC16mO strain is deleted, so that a B5R gene product having a normal function is not produced (Bell et al. (2004) Virology 325: 425-431). It is stated that deletion of the B5R gene may be deletion of a transmembrane domain, or deletion of not only a transmembrane domain but also some of SCR domains 1 to 4.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a recombinant vaccinia virus (in particular, oncolytic vaccinia virus), a pharmaceutical composition and a combination kit, for treating or preventing cancer.

As a result of extensively conducting studies in preparation of a vaccinia virus, the present inventors have prepared a vaccinia virus lacking functions of VGF and O1L and having a gene encoding B5R in which a region encoding an SCR domain in a B5R extracellular region has been deleted (Example 10), and the present inventors found importance of deletion of the SCR domain in the B5R extracellular region, and found that in a tumor-bearing mouse model, a tumor growth inhibitory action is continuously exhibited even after a decrease in the number of the vaccinia viruses is confirmed (Example 15). As a result of these findings, the vaccinia virus of the present invention has been provided, leading to completion of the present invention.

In exemplary embodiments, the present invention may include the following embodiments as medically or industrially useful substances or methods:

[A1] A vaccinia virus lacking functions of vaccinia virus growth factor (VGF) and O1L and having a gene encoding B5R in which an SCR (short consensus repeat) domain has been deleted.

[A2] The Vaccinia virus according to [A1], wherein the vaccinia virus has a gene encoding B5R in which SCR domains 1 to 4 have been deleted.

[A3] The vaccinia virus according to [A2], wherein the deletion of SCR domains 1 to 4 in B5R is deletion of a region corresponding to the amino acid sequence represented by SEQ ID NO: 24 in B5R.

[A4] The vaccinia virus according to any one of [A1] to [A3], wherein the gene encoding B5R in which an SCR domain has been deleted is a gene encoding a polypeptide comprising a signal peptide, a stalk, a transmembrane domain and a cytoplasmic tail of B5R.

[A5] The vaccinia virus according to any one of [A1] to [A4], wherein the B5R in which an SCR domain has been deleted consists of an amino acid sequence of B5R corresponding to the amino acid sequence of SEQ ID NO: 25.

[A6] The vaccinia virus according to any one of [A1] to [A5], wherein the vaccinia virus is an LC16mO strain.

[A7] A pharmaceutical composition comprising a vaccinia virus according to any one of [A1] to [A6] and a pharmaceutically acceptable excipient.

[A8] The pharmaceutical composition according to [A7], wherein the pharmaceutical composition is for prevention or treatment of a cancer.

As a result of considerable studies in the generation of vaccinia virus, the present inventors have generated vaccinia viruses comprising a polynucleotide encoding IL-7 or vaccinia viruses comprising a polynucleotide encoding IL-12, and vaccinia viruses comprising two polynucleotides, a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12 (Example 2); and found that 1) a vaccinia virus comprising two polynucleotides, a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12 and 2) a mixture of two vaccinia viruses, a vaccinia virus comprising a polynucleotide encoding IL-7 and a vaccinia virus comprising a polynucleotide encoding IL-12 exhibit a cytolytic effect on various human cancer cells (Example 3), thereby completing the present invention: 1) a vaccinia virus comprising two polynucleotides, a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12 could exhibit a tumor regression effect in cancer-bearing humanized mouse models (Example 6), could achieve complete remission (Example 7), and could induce acquired immunity to maintain the antitumor effect (Example 8) in syngeneic cancer-bearing mouse models. Moreover, 2) a mixture of two vaccinia viruses, a vaccinia virus comprising a polynucleotide encoding IL-7 and a vaccinia virus comprising a polynucleotide encoding IL-12 could achieve complete remission (Example 7), and could induce acquired immunity to maintain the antitumor effect (Example 8) in syngeneic cancer-bearing mouse models.

In exemplary embodiments, the present invention may encompass, as a substance or method useful in medicine or industry, the following inventions:

[B1] A vaccinia virus comprising the following (1) and (2):

-   -   (1) a polynucleotide encoding interleukin-7 (IL-7); and     -   (2) a polynucleotide encoding interleukin-12 (IL-12).

[B2] A pharmaceutical composition selected from the following (1) or (2):

-   -   (1) a pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-12 to be used in         combination with a pharmaceutical composition comprising a         vaccinia virus comprising a polynucleotide encoding IL-7; or     -   (2) a pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-7 to be used in         combination with a pharmaceutical composition comprising a         vaccinia virus comprising a polynucleotide encoding IL-12.

[B3] A combination kit comprising the following vaccinia viruses (1) and (2):

-   -   (1) a vaccinia virus comprising a polynucleotide encoding IL-7;         and     -   (2) a vaccinia virus comprising a polynucleotide encoding IL-12.

[B4] The vaccinia virus according to [B1], wherein the vaccinia virus is deficient in the function of vaccinia virus growth factor (VGF).

[B5] The vaccinia virus according to [B1], wherein the vaccinia virus is deficient in the function of O1L.

[B6] The vaccinia virus according to [B1], wherein the vaccinia virus is deficient in the functions of VGF and O1L.

[B7] The vaccinia virus according to [B1], wherein the vaccinia virus has a deletion in the short consensus repeat (SCR) domains in the B5R extracellular region.

[B8] The vaccinia virus according to [B1], wherein the vaccinia virus is deficient in the functions of VGF and O1L and has a deletion in the SCR domains in the B5R extracellular region.

[B9] The vaccinia virus according to any one of [B] and [BB4]-[8], wherein the vaccinia virus is a LC16mO strain.

[B10] A pharmaceutical composition comprising a vaccinia virus according to any one of [B] and [B4]-[B9] and a pharmaceutically acceptable excipient.

[B11] The pharmaceutical composition according to [B2] or the kit according to [B3], wherein the vaccinia virus is deficient in the function of VGF.

[B12] The pharmaceutical composition according to [B2] or the kit according to [B3], wherein the vaccinia virus is deficient in the function of O1L.

[B13] The pharmaceutical composition according to [B2] or the kit according to [B3], wherein the vaccinia virus is deficient in the functions of VGF and O1L.

[B14] The pharmaceutical composition according to [B2] or the kit according to [B3], wherein the vaccinia virus has a deletion in the SCR domains in the B5R extracellular region.

[B15] The pharmaceutical composition according to [B2] or the kit according to [B3], wherein the vaccinia virus is deficient in the functions of VGF and O1L and has a deletion in the SCR domains in the B5R extracellular region.

[B16] The pharmaceutical composition according to any one of [B2] and [B11]-[B15] or the kit according to any one of [B3] and [B11]-[B15], wherein the vaccinia virus is a LC16mO strain.

[B17] The pharmaceutical composition according to any one of [B2] and [B11]-[B16] or the kit according to any one of [B3] and [B11]-[B16], further comprising a pharmaceutically acceptable excipient.

[B18] The pharmaceutical composition or kit according to any one of [B10]-[B17], for preventing or treating cancer.

[B19] The pharmaceutical composition or kit according to [B18], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

[B20] A method for preventing or treating cancer, comprising the step of administering the vaccinia virus according to any one of [B] and [B4]-[B9] to a subject in need of the prevention or treatment for cancer.

[B21] The method according to [B20], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

[B22] The vaccinia virus according to any one of [B1] and [B4]-[B9], for use in preventing or treating cancer.

[B23] The vaccinia virus according to [B22], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

[B24] Use of the vaccinia virus according to any one of [B1] and [B4]-[B9] for the manufacture of a pharmaceutical composition for preventing or treating cancer.

[B25] The use according to [B24], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

[B26] A method for preventing or treating cancer, comprising the step of administering

-   -   (1) a vaccinia virus comprising a polynucleotide encoding IL-7;         and     -   (2) a vaccinia virus comprising a polynucleotide encoding IL-12         to a subject in need of the prevention or treatment for cancer.

[B27] The method according to [B26], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

[B28] A vaccinia virus selected from the following (1) or (2):

-   -   (1) a vaccinia virus comprising a polynucleotide encoding IL-7,         for preventing or treating cancer in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-12; or     -   (2) a vaccinia virus comprising a polynucleotide encoding IL-12,         for preventing or treating cancer in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-7.

[B29] The vaccinia virus according to [B28], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

[B30] Use of a vaccinia virus selected from the following (1) or (2):

-   -   (1) use of a vaccinia virus comprising a polynucleotide encoding         IL-7 for the manufacture of a pharmaceutical composition for         preventing or treating cancer to be used in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-12; or     -   (2) use of a vaccinia virus comprising a polynucleotide encoding         IL-12 for the manufacture of a pharmaceutical composition for         preventing or treating cancer to be used in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-7.

[B31] The use according to [B30], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

[B32] Use of (1) a vaccinia virus comprising a polynucleotide encoding IL-7 and (2) a vaccinia virus comprising a polynucleotide encoding IL-12 for the manufacture of a combination kit for preventing or treating cancer.

[B33] The use according to [B32], wherein the cancer is malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer or gastric cancer.

A vaccinia virus of the present invention and a pharmaceutical composition of the present invention exhibits a tumor growth inhibitory action, and can be used for prevention or treatment of a cancer.

The vaccinia virus carrying IL-7 and IL-12 according to the present invention and the vaccinia viruses contained in the pharmaceutical composition and combination kit according to the present invention exhibit oncolytic activity, express IL-12 and IL-7 polypeptides encoded by polynucleotides carried by the viruses in cancer cells, and induce complete remission and acquired immunity. The vaccinia virus, pharmaceutical composition, and combination kit according to the present invention can be used for preventing or treating cancer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing illustrating an example of transfer vector plasmid DNAs used in the present invention, in which the upper map illustrates an example in which the BFP gene operably linked to a promoter is incorporated in the VGF gene and the lower map illustrates an example in which the BFP gene operably linked to a promoter is incorporated in the O1L gene.

FIG. 2 is a schematic view of the genome structure of recombinant vaccinia viruses (LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-LacZ and viruses constructed in the process of generating the virus vector).

FIG. 3 is a schematic view of the genome structure of recombinant vaccinia viruses (LC16mO ΔSCR VGF-SP-IL12/O1L-SP-LacZ, LC16mO ΔSCR VGF-SP-IL7/O1L-SP-LacZ).

FIG. 4 is a schematic view of the genome structure of a recombinant vaccinia virus (LC16mO ΔSCR VGF-SP-IL12/O1L-SP-IL7).

FIG. 5A is a graph illustrating oncolytic properties of a recombinant vaccinia virus (LC16mO ΔSCR VGF-SP-IL12/O1L-SP-IL7), in which the ordinate represents the cancer cell survival rate (%) and the error bars represent standard deviation. FIG. 5B is a graph illustrating oncolytic properties of a recombinant vaccinia virus (LC16mO ΔSCR VGF-SP-IL12/O1L-SP-IL7), in which the ordinate represents cancer cell survival rate (%) and the error bars represents standard deviation, FIG. 5A and FIG. 5B being graphs obtained under the same experimental conditions except that the cell types measured were different. FIG. 5C is a graph illustrating oncolytic properties of a mixture of 2 recombinant vaccinia viruses (a mixture of LC16mO ΔSCR VGF-SP-IL12/O1L-SP-LacZ and LC16mO ΔSCR VGF-SP-IL7/O1L-SP-LacZ), in which the ordinate represents cancer cell survival rate (%) and the error bars represent standard deviation. FIG. 5D is a graph illustrating oncolytic properties of a mixture of 2 recombinant vaccinia viruses (a mixture of LC16mO ΔSCR VGF-SP-IL12/O1L-SP-LacZ and LC16mO ΔSCR VGF-SP-IL7/O1L-SP-LacZ), in which the ordinate represents cancer cell survival rate (%) and the error bars represent standard deviation, FIG. 5C and FIG. 5D being graphs obtained under the same experimental conditions except that the cell types measured were different.

FIG. 6 shows structures of a recombinant vaccinia virus LC16mO VGF-SP-LucGFP/O1-SP-BFP (B5R virus) (FIG. 6A) and LC16mO ΔSCR VGF-SP-LucGFP/O1-SP-BFP (ΔSCR virus) (FIG. 6B).

FIG. 7A shows fluorescent observation images of four kinds of ovarian cancer cells at 120 hours after infection with an intracellular mature virus (IMV) from a B5R virus or a ΔSCR virus. FIG. 7B shows fluorescent observation images of four kinds of ovarian cancer cells at 120 hours after infection with an EEV from a B5R virus or a ΔSCR virus

FIG. 8 shows cell survival rates of four kinds of ovarian cancer cells at 120 hours after infection with an IMV (FIG. 8A) or an EEV (FIG. 8B) from a B5R virus or a ΔSCR virus

FIG. 9 shows fluorescently observed growth of each virus after an EEV (FIG. 9A) or an IMV (FIG. 9B) derived from a B5R virus or a ΔSCR virus is mixed with rabbit anti-vaccinia virus serum and a rabbit complement.

FIG. 10 shows a hybrid count of each virus after an EEV (FIG. 10A) or an IMV (FIG. 10B) derived from a B5R virus or a ΔSCR virus is mixed with rabbit anti-vaccinia virus serum and a rabbit complement.

FIG. 11A shows virus distributions in a body at 3 days (Day 3) and 7 days (Day 7) after administration of an EEV derived from a B5R virus or a ΔSCR virus in a mouse model peritoneally inoculated with human ovarian cancer A2780 to which anti-vaccinia virus serum has been administered. FIG. 11B shows tumor growth at 3 days (Day 3) and 8 days (Day 8) after administration of an EEV derived from a B5R virus or a ΔSCR virus in a mouse model peritoneally inoculated with human ovarian cancer A2780 to which anti-vaccinia virus serum has been administered.

FIG. 12 shows the result of quantification of virus growth (FIG. 12A) or the result of quantification of tumor growth (FIG. 12B) after administration of an EEV derived from a B5R virus or a ΔSCR virus in a mouse model peritoneally inoculated with human ovarian cancer A2780 to which anti-vaccinia virus serum has been administered

FIG. 13 shows a survival ratio after administration of an EEV derived from a B5R virus or a ΔSCR virus in a mouse model peritoneally inoculated with human ovarian cancer A2780 under the presence or absence of anti-vaccinia virus serum.

FIG. 14 shows a tumor volume on the virus administration side (upper view in FIG. 14) or a tumor volume on the virus non-administration side (lower view in FIG. 14) in a mouse model bearing mouse colorectal cancer CT26 cells on both sides to which a B5R-LL virus or a ΔSCR-LL virus has been administered.

FIG. 15 shows the amount of viruses on the virus administration side in a mouse model bearing mouse colorectal cancer CT26 cells on both sides to which a B5R-LL virus or a ΔSCR-LL virus has been administered.

FIG. 16 is a schematic view of a B5R region.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a vaccinia virus having a gene encoding B5R in which an SCR domain has been deleted. The present invention also provides a vaccinia virus lacking functions of VGF and O1L and having a gene encoding B5R in which an SCR domain has been deleted (herein, the vaccinia virus is also referred to as a “vaccinia virus of the present invention”). The vaccinia virus, the pharmaceutical composition, and the combination kit according to the present invention are useful for preventing or treating various cancers.

The vaccinia virus of the present invention is a virus belonging to Poxviridae Orthopoxvirus. Examples of the vaccinia virus strain for use in the present invention include, but are not limited to, Lister strain, New York City Board of Health (NYBH) strain, Wyeth strain, Copenhagen strain, Western Reserve (WR) strain, Modified Vaccinia Ankara (MVA) strain, EM63 strain, Ikeda strain, Dairen strain and Tian Tan strain, and Lister strain and MVA strain are available from American Type Culture Collection (ATCC) (registered trademark) (ATCC (registered trademark) VR-1549 and ATCC (registered trademark) VR-1508, respectively). Further, vaccinia virus strains established with the-above-mentioned strains as origins can be used as vaccinia viruses for use in the present invention. For example, as a vaccinia virus for use in the present invention, LC16 strain, LC16m8 strain and LC16mO strain established from Lister strain can also be used. The LC16mO strain is a strain created by way of LC16 strain obtained by subculturing Lister strain as a parent strain at a low temperature. The LC16m8 strain is a strain which is created by further subculturing the LC16mO strain at a low temperature and which is attenuated because frameshift mutation occurs in a B5R gene as a gene encoding viral membrane protein, so that the protein is no longer expressed and caused to function (Protein, Nucleic Acid and Enzyme (2003) 48: 1693-1700). As complete genome sequences of Lister strain, LC16m8 strain and LC16mO strain, for example, Accession No. AY678276.1, Accession No. AY678275.1 and Accession No. AY678277.1, respectively. Therefore, LC16m8 strain and LC16mO strain can be prepared from Lister strain by a known homologous recombination or site-specific mutagenesis introduction method

In one embodiment, the vaccinia virus for use in the present invention is LC16mO strain.

B5R (Accession No. AAA48316.1) is a type 1 membrane protein resides in the envelope of vaccinia virus, and serves to increase the infection efficiency when the virus infects and is transmitted to neighboring cells or other sites in the host. The extracellular region of B5R contains 4 structural domains called SCR domains (Herrera et al. (1998) Journal of Virology 72: 294-302). In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit has (have) a deletion in the SCR domains in the extracellular region of B5R.

The deletion in the SCR domains in the B5R extracellular region of vaccinia virus encompasses the deletion of a part or all of the 4 SCR domains in the B5R extracellular region and refers to the lack of expression of a gene region encoding a part or all of the 4 SCR domains in the B5R extracellular region or the lack of a part or all of the 4 SCR domains in the extracellular region in the expressed B5R protein. In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit has (have) the deletion of all 4 SCR domains. In one embodiment, the 4 SCR domains deleted in the vaccinia virus according to the present invention, the vaccinia virus to be used in combination, and the vaccinia viruses for the combination kit correspond to the region from amino acid 22 to amino acid 237 in the amino acid sequence of Accession No. AAA48316.1 described above.

Whether or not the vaccinia virus according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit has/have a deletion in the SCR domains in the B5R extracellular region can be determined with a known method, for example, by testing for the presence of the SCR domains by an immunochemical technique using an antibody against the SCR domains or determining the presence or the size of the gene encoding the SCR domains by PCR.

In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit is/are vaccinia virus deficient in the functions of VGF and O1L and having a deletion in the SCR domains in the B5R extracellular region.

In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit are vaccinia virus of the strain LC16mO deficient in the functions of VGF and O1L and having a deletion in the SCR domains in the B5R extracellular region.

More specifically, B5R is type 1 membrane protein of vaccinia virus. At the time when a virus grows in a cell, and at the time when a virus is transmitted to a neighboring cell or other site in a host body, B5R serves to improve the efficiency of the growth and transmission. Examples of the B5R include B5R having an amino acid sequence registered in Accession No. AAA48316.1. The B5R has a signal peptide, four regions called SCR domains (SCR domains 1 to 4), a region called a stalk, a transmembrane domain and a cytoplasmic tail in this order from the N-terminal side to the C-terminal side (FIG. 16; in FIG. 16, signal peptide, stalk, transmembrane domain and cytoplasmic tail are referred, respectively, to SP, S, TM and CT). More specifically, in the B5R, for example, the signal peptide is a region of B5R corresponding to the 1st to 19th amino acids in the amino acid sequence registered in AAA48316.1, the SCR domains 1 to 4 are regions of BR5 corresponding to the 20th to 237th amino acids in the amino acid sequence registered in AAA48316.1, The stalk is a region of BR5 corresponding to the 238th to 275th amino acids in the amino acid sequence registered in AAA48316.1, the transmembrane domain is a region of B5R corresponding to the 276th to 303rd amino acids in the amino acid sequence registered in AAA48316.1, and the cytoplasmic tail is a region of B5R corresponding to the 304th to 317th amino acids in the amino acid sequence registered in AAA48316.1 (Aldaz-Carroll et al. (2005) Journal of Virology 79: 6260-6271). The phrase “corresponding to” is not limited to the presence of an amino acid sequence completely and accurately coincident with an amino acid sequence specified by this phrase, but is a concept encompassing the presence of an amino acid sequence deviated from an amino acid sequence specified by this phrase (e.g. an amino acid is deleted, replaced, inserted and/or added) due to, for example, a difference in protein function analysis method and vaccinia virus strain. Those skilled in the art will be able to identify the gene of B5R and the regions of B5R in each of different vaccinia virus strains on the basis of the amino acid sequences. When the B5R is expressed on the outer membrane of EEV, the signal peptide is removed, and the SCR domains 1 to 4 and the stalk are exposed on the external membrane of EEV (Herrera et al. (1998) Journal of Virology 72(1): 294-302). Herein, a region consisting of SCR domains 1 to 4 and a stalk is sometimes referred to as an “extracellular region”.

In the vaccinia virus according to the present invention, “gene encoding B5R in which an SCR domain has been deleted” encompasses genes encoding B5R in which some or all of SCR domains 1 to 4 have been deleted and thereby the function has been deteriorated. Examples of methods for determining whether the function of B5R has been deteriorated in a vaccinia virus include methods of checking whether the neutralization escape ability against a neutralizing antibody targeting B5R has been enhanced as compared with vaccinia viruses without deletion of an SCR domain. An example of methods of checking neutralization escape ability is a method described later in Example 5. In an embodiment, B5R in which an SCR domain has been deleted has an extracellular region of B5R excluding the deleted region. In an embodiment, B5R in which an SCR domain has been deleted has an extracellular region and a transmembrane domain of B5R excluding the deleted region. In an embodiment, B5R in which an SCR domain has been deleted has an extracellular region, a transmembrane domain and a cytoplasmic tail of B5R excluding the deleted region. In an embodiment, B5R in which an SCR domain has been deleted has a stalk. In an embodiment, B5R in which an SCR domain has been deleted has a stalk and a transmembrane domain. In an embodiment, B5R in which an SCR domain has been deleted has a stalk, a transmembrane domain and a cytoplasmic tail. In an embodiment, the vaccinia virus according to the present invention is capable of displaying B5R having an extracellular region in which some or all of SCR domains 1 to 4 have been deleted to the virus surface when the vaccinia virus has changed to the EEV form.

In an embodiment, “B5R in which an SCR domain has been deleted” in the vaccinia virus according to the present invention is B5R in which four SCR domains (SCR domains 1 to 4) have been deleted. The expression “deletion of SCR domains 1 to 4” and similar expressions presented in a context regarding the four SCR domains each have a concept including not only complete and exact deletion of a region composed of SCR domains 1 to 4, but also a situation that one, two, or three amino acids present in an end of the region remain in B5R. Examples of deletion of SCR domains 1 to 4 in the vaccinia virus according to the present invention include deletion of a B5R region corresponding to an amino acid sequence from the 22nd amino acid to the 237th amino acid of an amino acid sequence registered under Accession No. AAA48316.1. The amino acid sequence from the 22nd amino acid to the 237th amino acid of an amino acid sequence registered under Accession No. AAA48316.1 is represented by SEQ ID NO: 24. In an embodiment, deletion of SCR domains 1 to 4 in B5R of the vaccinia virus according to the present invention is deletion of a region corresponding to the amino acid sequence represented by SEQ ID NO: 24 in B5R. Those skilled in the art could specify a region corresponding to the amino acid sequence represented by SEQ ID NO: 24 in B5R of a different vaccinia virus strain. In an embodiment, deletion of SCR domains 1 to 4 in B5R of the vaccinia virus according to the present invention is deletion of a region consisting of the amino acid sequence represented by SEQ ID NO: 24 in B5R.

In an embodiment, B5R in which SCR domains 1 to 4 have been deleted has an extracellular region of B5R excluding the deleted region. In an embodiment, B5R in which SCR domains 1 to 4 have been deleted has an extracellular region and a transmembrane domain of B5R excluding the deleted region. In an embodiment, B5R in which SCR domains 1 to 4 have been deleted has an extracellular region, a transmembrane domain and a cytoplasmic tail of B5R excluding the deleted region. In an embodiment, B5R in which SCR domains 1 to 4 have been deleted has a stalk. In an embodiment, B5R in which SCR domains 1 to 4 have been deleted has a stalk and a transmembrane domain. In an embodiment, B5R in which SCR domains 1 to 4 have been deleted has a stalk, a transmembrane domain and a cytoplasmic tail. In an embodiment, the vaccinia virus according to the present invention is capable of displaying B5R having an extracellular region in which SCR domains 1 to 4 have been deleted to the virus surface when the vaccinia virus has changed to the EEV form.

In an embodiment, B5R in which an SCR domain has been deleted has a region of B5R corresponding to an amino acid sequence from the 238th amino acid to the 275th amino acid of an amino acid sequence registered under Accession No. AAA48316.1 (consisting of an amino acid sequence of the amino acid numbers 22 to 59 of SEQ ID NO: 25). In an embodiment, B5R in which an SCR domain has been deleted has a region of B5R corresponding to an amino acid sequence from the 238th amino acid to the 303rd amino acid of an amino acid sequence registered under Accession No. AAA48316.1 (consisting of an amino acid sequence of the amino acid numbers 22 to 87 of SEQ ID NO: 25). In an embodiment, B5R in which an SCR domain has been deleted has a region of B5R corresponding to an amino acid sequence from the 238th amino acid to the 317th amino acid of an amino acid sequence registered under Accession No. AAA48316.1 (consisting of an amino acid sequence of the amino acid numbers 22 to 101 of SEQ ID NO: 25).

In an embodiment, the gene encoding B5R in which an SCR domain has been deleted in the vaccinia virus according to the present invention encodes a signal peptide of B5R. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide of B5R and an extracellular region of B5R excluding the deleted region. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide of B5R and an extracellular region and a transmembrane domain of B5R excluding the deleted region. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide of B5R and an extracellular region, a transmembrane domain and a cytoplasmic tail of B5R excluding the deleted region. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide and a stalk of B5R. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide, a stalk and a transmembrane domain of B5R. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide, a stalk, a transmembrane domain and a cytoplasmic tail of B5R. In an embodiment, the gene encoding B5R in which SCR domains 1 to 4 have been deleted encodes a polypeptide consisting essentially of a signal peptide of B5R and an extracellular region, a transmembrane domain and a cytoplasmic tail of B5R excluding the deleted region. In an embodiment, the gene encoding B5R in which SCR domains 1 to 4 have been deleted encodes a polypeptide consisting essentially of a signal peptide, a stalk, a transmembrane domain and a cytoplasmic tail of B5R. “Consisting essentially of” as used herein is intended to include an element or elements specified by the phrase, and an additional element can be included; however, the additional element is limited to elements that do not interfere with activity or action disclosed herein for the recited elements or that do not contribute to the activity or action. For example, a mode with addition or deletion of one to several amino acids is an example of modes specified by “consisting essentially of”. Examples of the signal peptide of B5R include a region of B5R corresponding to an amino acid sequence from the 1st amino acid to the 19th amino acid of an amino acid sequence registered under Accession No. AAA48316.1 (an amino acid sequence of the amino acid numbers 1 to 19 of SEQ ID NO: 25). Examples of the stalk of B5R include a region of B5R corresponding to an amino acid sequence from the 238th amino acid to the 275th amino acid of an amino acid sequence registered under Accession No. AAA48316.1 (an amino acid sequence of the amino acid numbers 22 to 59 of SEQ ID NO: 25). Examples of the transmembrane domain of B5R include a region of B5R corresponding to an amino acid sequence from the 276th amino acid to the 303rd amino acid of an amino acid sequence registered under Accession No. AAA48316.1 (an amino acid sequence of the amino acid numbers 60 to 87 of SEQ ID NO: 25). Examples of the cytoplasmic tail of B5R include a region of B5R corresponding to an amino acid sequence from the 304th amino acid to the 317th amino acid of an amino acid sequence registered under Accession No. AAA48316.1 (an amino acid sequence of the amino acid numbers 88 to 101 of SEQ ID NO: 25). In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a signal peptide of B5R corresponding to an amino acid sequence of the amino acid numbers 1 to 19 of SEQ ID NO: 25. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a signal peptide consisting of an amino acid sequence of the amino acid numbers 1 to 19 of SEQ ID NO: 25. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide of B5R corresponding to an amino acid sequence of the amino acid numbers 1 to 19 of SEQ ID NO: 25 and a stalk of B5R corresponding to an amino acid sequence of the amino acid numbers 22 to 59 of SEQ ID NO: 25. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide consisting of an amino acid sequence of the amino acid numbers 1 to 19 of SEQ ID NO: 25 and a stalk consisting of an amino acid sequence of the amino acid numbers 22 to 59 of SEQ ID NO: 25. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide of B5R corresponding to an amino acid sequence of the amino acid numbers 1 to 19 of SEQ ID NO: 25, a stalk of B5R corresponding to an amino acid sequence of the amino acid numbers 22 to 59 of SEQ ID NO: 25 and a transmembrane domain of B5R corresponding to an amino acid sequence of the amino acid numbers 60 to 87 of SEQ ID NO: 25. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide including a signal peptide consisting of an amino acid sequence of the amino acid numbers 1 to 19 of SEQ ID NO: 25, a stalk of B5R consisting of an amino acid sequence of the amino acid numbers 22 to 59 of SEQ ID NO: 25 and a transmembrane domain of B5R consisting of an amino acid sequence of the amino acid numbers 60 to 87 of SEQ ID NO: 25. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide consisting of an amino acid sequence of B5R corresponding to the amino acid sequence of SEQ ID NO: 25. In an embodiment, the gene encoding B5R in which an SCR domain has been deleted encodes a polypeptide consisting of the amino acid sequence of SEQ ID NO: 25.

Whether the vaccinia virus according to the present invention is encoding B5R in which some or all of SCR domains 1 to 4 have been deleted can be determined by using a known method. For example, determination can be made by checking B5R expressed on the surface of the vaccinia virus for the presence of SCR domains 1 to 4 through an immunochemical technique with antibodies to bind to SCR domains 1 to 4, or by determining the presence or size of a region encoding SCR domains 1 to 4 in the B5R gene through polymerase chain reaction (PCR).

In a preferred embodiment, the vaccinia virus according to the present invention is a vaccinia virus lacking functions of VGF and O1L. Vaccinia viruses can be forced to lack function(s) of VGF and/or O1L in accordance with a method described in International Publication No. WO 2015/076422.

VGF, which is a protein having a high amino acid sequence homology to epidermal growth factor (EGF), binds to an epidermal growth factor receptor similarly to EGF to activate signal cascade including Ras, Raf, mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) (MAPK/ERK kinase (MEK)), and ERK in the order presented, thereby accelerating cell division.

O1L maintains activation of ERK, and contributes to cell division in combination with VGF.

Lack of functions of VGF and O1L of a vaccinia virus refers to a situation that a gene encoding VGF and a gene encoding O1L are not expressed or a situation that the genes are expressed but the expressed proteins do not possess the normal functions of VGF and O1L of a vaccinia virus. To force a vaccinia virus to lack functions of VGF and O1L, it is suitable to delete the entire or part of each of a gene encoding VGF and a gene encoding O1L. Alternatively, genes may be mutated to prevent expression of normal VGF and O1L through substitution, deletion, insertion or addition of a nucleotide. A foreign gene may be inserted into each of a gene encoding VGF and a gene encoding O1L. In the present invention, if a normal functional gene product is not expressed because of mutation such as substitution, deletion, insertion and addition of a gene, the gene is said to be lacked. For example, a cytokine to activate an immune function can be introduced as a foreign gene.

Whether the vaccinia virus according to the present invention is lacking functions of VGF and O1L can be determined by using a known method. For example, determination can be made by evaluating functions of VGF and O1L, checking the presence of VGF or O1L through an immunochemical technique with an antibody to VGF or an antibody to O1L, or determining the presence of a gene encoding VGF or a gene encoding O1L through PCR.

In an embodiment, the vaccinia virus according to the present invention is a vaccinia virus lacking functions of VGF and OIL and having a gene encoding B5R in which an SCR domain has been deleted. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk and a transmembrane domain. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is a vaccinia virus lacking functions of VGF and OIL and having a gene encoding B5R in which SCR domains 1 to 4 have been deleted. In this embodiment, B5R in which SCR domains 1 to 4 have been deleted can have a stalk. In this embodiment, B5R in which SCR domains 1 to 4 have been deleted can have a stalk and a transmembrane domain. In this embodiment, B5R in which SCR domains 1 to 4 have been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is a vaccinia virus lacking functions of VGF and OIL and having a gene encoding B5R in which a region corresponding to the amino acid sequence represented by SEQ ID NO: 24 has been deleted. In this embodiment, B5R in which the region has been deleted can have a stalk. In this embodiment, B5R in which the region has been deleted can have a stalk and a transmembrane domain. In this embodiment, B5R in which the region has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is a vaccinia virus lacking functions of VGF and O1L in which a polypeptide including a signal peptide, a stalk, a transmembrane domain and a cytoplasmic tail of B5R is encoded, where an SCR domain of B5R has been deleted. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is a vaccinia virus lacking functions of VGF and O1L in which B5R in which an SCR domain has been deleted consists of an amino acid sequence of B5R corresponding to the amino acid sequence of SEQ ID NO: 25. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is an LC16mO strain vaccinia virus lacking functions of VGF and O1L and having a gene encoding B5R in which an SCR domain has been deleted. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk and a transmembrane domain. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is an LC16mO strain vaccinia virus lacking functions of VGF and O1L and having a gene encoding B5R in which SCR domains 1 to 4 have been deleted. In this embodiment, B5R in which SCR domains 1 to 4 have been deleted can have a stalk. In this embodiment, B5R in which SCR domains 1 to 4 have been deleted can have a stalk and a transmembrane domain. In this embodiment, B5R in which SCR domains 1 to 4 have been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is an LC16mO strain vaccinia virus lacking functions of VGF and O1L and having a gene encoding B5R in which a region corresponding to the amino acid sequence represented by SEQ ID NO: 24 has been deleted. In this embodiment, B5R in which the region has been deleted can have a stalk. In this embodiment, B5R in which the region has been deleted can have a stalk and a transmembrane domain. In this embodiment, B5R in which the region has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is an LC16mO strain vaccinia virus lacking functions of VGF and O1L and having a gene encoding a polypeptide including a signal peptide, a stalk, a transmembrane domain and a cytoplasmic tail of B5R, where an SCR domain of B5R has been deleted. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

In an embodiment, the vaccinia virus according to the present invention is an LC16mO strain vaccinia virus lacking functions of VGF and O1L in which B5R in which an SCR domain has been deleted consists of an amino acid sequence of B5R corresponding to the amino acid sequence of SEQ ID NO: 25. In this embodiment, B5R in which an SCR domain has been deleted can have a stalk, a transmembrane domain and a cytoplasmic tail.

The vaccinia virus to be used in the present invention can be attenuated and/or modified with respect to tumor selectivity. “Attenuated” as used herein means that toxicity (e.g., cytolytic ability) to normal cells (e.g., non-tumor cells) is lower. “Tumor selectivity” as used herein means that toxicity (e.g., cytolytic ability) to tumor cells is higher than that to normal cells (e.g., non-tumor cells). The vaccinia virus to be used in the present invention may be further subjected in advance to genetic modification such that lack of a function of a specific protein is caused or expression of a specific gene or protein is suppressed (Guse et al. (2011) Expert Opinion on Biological Therapy 11: 595-608). To enhance the tumor selectivity of a vaccinia virus, for example, an operation can be performed, such as causing lack of a function of TK (Yamabe et al. (1999) Cancer Gene Therapy 6: 409-422), introduction of a modified TK gene and a modified hemagglutinin (HA) gene, and a modified F3 gene or a truncated F3 locus (International Publication No. WO 2005/047458), causing lack of functions of TK and HA, and F14.5L (Zhang et al. (2007) Cancer Research 67: 10038-10046), causing lack of functions of TK and B18R (Kirn et al. (2007) PLoSMedicine 4: e353), causing lack of functions of TK and ribonucleotide reductase (Gammon et al. (2010) PLoSPathogens 6: e1000984), causing lack of functions of SPI-1 and SPI-2 (Guo et al. (2005) Cancer Research 65: 9991-9998), causing lack of functions of SPI-1, SPI-2 and TK (Yang et al. (2007) Gene Therapy 14: 638-647), and introduction of mutation into E3L and K3L regions (International Publication No. WO 2005/007824). With an expectation of reduction of exclusion of viruses due to the neutralization effect of an anti-vaccinia virus antibody in the living body, lack of an A34R region can be caused (Thirunavukarasu et al. (2013) Molecular Therapy 21: 1024-1033). With an expectation of an effect of a vaccinia virus to activate immune cells, lack of an interleukin-lb (IL-lb) receptor can be caused ((International Publication No. WO 2005/030971). Such insertion of a foreign gene and deletion or mutation of a gene can be performed, for example, by using known homologous recombination or site-specific mutagenesis. The vaccinia virus according to the present invention may have combination of such genetic modifications. “Lack” as used herein means that a gene region specified by the term has no function, and is intended to include a situation that a gene region specified by the term is deleted. For example, “lack” may refer to the presence of deletion in a region consisting of a specified gene region, or the presence of deletion in a gene region around a specified gene region with the specified gene region included therein.

Vaccinia viruses can be in the IMV form and the EEV form. IMVs account for most of infectious progeny viruses, and remain in the cytoplasm of an infected cell until the lysis of the infected cell. When cells are infected with a vaccinia virus in the IMV form, the vaccinia virus can force the infected cells to produce the EEV form. The EEV form is a form suitable for remote infection of cells far from an infection site in the living body, the form being such that an outer membrane derived from a host is covering an IMV. EEVs can be obtained from supernatant of culture solution for cells infected with a vaccinia virus-producing vector or a vaccinia virus. IMVs can be obtained from the cell bodies of cells infected with a vaccinia virus-producing vector or a vaccinia virus. The form of a mixture of IMVs and EEVs can be obtained from cell lysate containing supernatant of culture solution for cells infected with a vaccinia virus-producing vector or a vaccinia virus. The cell lysate can be obtained in accordance with a conventional method such as crushing of cells by sonication or osmotic shock. The IMV form is an example of primary modes of administration of a vaccinia virus.

In an embodiment, the vaccinia virus according to the present invention is capable of displaying an extracellular region of B5R in which an SCR has been deleted when the vaccinia virus has changed to the EEV form; however, the vaccinia virus does not necessarily need to be in the EEV form at all times, and is only required to be capable of displaying an extracellular region of B5R in which an SCR has been deleted when infected cells are forced to produce the EEV form.

The vaccinia virus according to the present invention can produce an EEV having higher immune evasion ability than a vaccinia virus having a gene encoding wild-type B5R without deletion of an SCR, and hence can be called remote-infectious trait-strengthened recombinant vaccinia virus.

A polynucleotide encoding an exogenous polypeptide can be introduced into the vaccinia virus according to the present invention by a known technique, such as homologous recombination or site-directed mutagenesis. For example, a plasmid in which the polynucleotide is introduced in a nucleotide sequence of the site where the introduction (also referred to as the “transfer vector plasmid DNA”.) is intended can be constructed and introduced in the cells infected with the vaccinia virus. Preferably, the introduction region of the polynucleotide is a gene region that is not indispensable to the life cycle of the vaccinia virus. For example, in a certain aspect, the region is within either or both of the VGF gene and the O1L gene. In the above process, the polynucleotide encoding an exogenous polypeptide can be introduced so that it is transcribed in the same direction as or in the opposite direction of the direction of the transcription of the VGF and O1L genes. Examples of the polynucleotide encoding an exogenous polypeptide include, but are not limited to, a marker, a therapeutic product having cytotoxicity or immunopotentiating effect, or a polynucleotide encoding an antigen.

The method for introducing the transfer vector plasmid DNA into cells is not particularly limited, but examples thereof include the calcium phosphate method and electroporation.

In the introduction of the polynucleotide encoding an exogenous polypeptide, an appropriate promoter can be operably linked to the upstream of the polynucleotide to be introduced. In this way, the polynucleotide encoding an exogenous polypeptide can be linked to a promoter that can initiate the expression in tumor cells in the vaccinia virus according to the present invention. Examples of such a promoter include PSFJ1-10, PSFJ2-16, p7.5K promoter, p11K promoter, T7.10 promoter, CPX promoter, HF promoter, H6 promoter, and T7 hybrid promoter.

In one embodiment, the vaccinia virus according to the present invention has no drug-selectable marker gene.

The vaccinia virus according to the present invention has oncolytic activity. Examples of a method for determining whether a test virus has oncolytic activity include methods for evaluating the decrease in survival rate of cancer cells by addition of the virus. Examples of the cancer cells to be used in the evaluation include, but are not limited to, ovarian cancer cells A2780 (for example, ECACC 93112519), CaOV3 (for example, ATCC® HTB-75), RMG-1 (for example, JCRB JCRB0172), and SKOV3 (for example, ATCC® HTB-77). The examples also include malignant melanoma cells RPMI-7951 (for example, ATCC® HTB-66), lung cancer cells A549 (for example, ATCC® CCL-185), lung adenocarcinoma cells HCC4006 (for example, ATCC® CRL-2871), small cell lung carcinoma cells DMS 53 (for example, ATCC® CRL-2062), squamous cell lung cancer cells NCI-H226 (for example, ATCC® CRL-5826), kidney carcinoma cells Caki-1 (for example, ATCC® HTB-46), bladder cancer cells 647-V (for example, DSMZ ACC 414), head and neck carcinoma cells Detroit 562 (for example, ATCC® CCL-138), breast cancer cells JIMT-1 (for example, DSMZ ACC 589), breast cancer cells MDA-MB-231 (for example, ATCC® HTB-26), esophageal carcinoma cells OE33 (for example, ECACC 96070808), glioblastoma U-87MG (for example, ECACC 89081402), neuroblastoma GOTO (for example, JCRB JCRB0612), myeloma RPMI 8226 (for example, ATCC® CCL-155), ovarian cancer cells SK-OV-3 (for example, ATCC® HTB-77), ovarian cancer cells OVMANA (for example, JCRB JCRB 1045), colorectal cancer cells RKO (for example, ATCC® CRL-2577), colorectal cancer cells HCT 116 (for example, ATCC® CCL-247), pancreatic cancer cells BxPC3 (for example, ATCC® CRL-1687), prostate cancer cells LNCaP clone FGC (for example, ATCC® CRL-1740), liver carcinoma cells JHH-4 (for example, JCRB JCRB0435), mesothelioma NCI-H28 (for example, ATCC® CRL-5820), cervical carcinoma cells SiHa (for example, ATCC® HTB-35), and gastric cancer cells Kato III (for example, RIKEN BRC RCB2088). Specific examples a method of evaluation include the method described in Example 4 below.

The vaccinia virus according to the present invention can be expressed and/or proliferated by infecting host cells with the vaccinia virus and culturing the infected host cells. The vaccinia virus can be expressed and/or proliferated by a method known in the field. The host cells to be used in the expression or proliferation of the vaccinia virus according to the present invention is not particularly limited, as long as they can express and proliferate the vaccinia virus according to the present invention. Examples of such host cells include animal cells such as BS-C-1, A549, RK13, HTK-143, Hep-2, MDCK, Vero, HeLa, CV-1, COS, BHK-21, and primary rabbit kidney cells and preferable examples include BS-C-1 (ATCC® CCL-26), A549 (ATCC® CCL-185), CV-1 (ATCC® CCL-70), or RK13 (ATCC® CCL-37). The conditions, for example, temperature, pH of the medium, and the culture time, for culturing the host cells are selected as appropriate.

The method for producing vaccinia virus according to the present invention may further include, in addition to the steps of infecting host cells with the vaccinia virus according to the present invention, culturing the infected host cells, and expressing the vaccinia virus according to the present invention, the step of collecting, preferably purifying, isolating, or concentrating, the vaccinia virus according to the present invention. The method for purification, isolation, or concentration may be a method well known to those skilled in the art and examples thereof include DNA digestion using Benzonase, sucrose gradient centrifugation, lodixanol density gradient centrifugation, ultrafiltration, and diafiltration.

The vaccinia virus according to the present invention may contain a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12. The vaccinia virus according to the present invention may contain a polynucleotide encoding IL-7, and may be used in combination with another vaccinia virus according to the present invention, which another vaccinia virus contains a polynucleotide encoding IL-12. The vaccinia virus according to the present invention may contain a polynucleotide encoding IL-12, and may be used in combination with another vaccinia virus according to the present invention, which another vaccinia virus contains a polynucleotide encoding IL-7. The vaccinia virus containing a polynucleotide encoding IL-7 and/Or a polynucleotide encoding IL-12 will be described below.

Vaccinia virus carrying IL-7 and IL-12, pharmaceutical composition to be used in combination and combination kit according to the present invention

The present invention provides a vaccinia virus comprising the following (1) and (2):

-   -   (1) a polynucleotide encoding IL-7; and     -   (2) a polynucleotide encoding IL-12.

As used herein, the vaccinia virus is also referred to as the “vaccinia virus carrying IL-7 and IL-12 according to the present invention”.) The vaccinia virus carrying IL-7 and IL-12 according to the present invention can be produced, for example but not limited to, by introducing (1) and (2) above into the vaccinia virus according to the present invention.

The present invention also provides a pharmaceutical composition selected from the following (1) or (2):

-   -   (1) a pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-12 to be used in         combination with a pharmaceutical composition comprising a         vaccinia virus comprising a polynucleotide encoding IL-7; or     -   (2) a pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-7 to be used in         combination with a pharmaceutical composition comprising a         vaccinia virus comprising a polynucleotide encoding IL-12.

As used herein, the pharmaceutical composition is also referred to as the “pharmaceutical composition to be used in combination according to the present invention” and a vaccinia virus comprising a polynucleotide encoding IL-7 or a vaccinia virus comprising a polynucleotide encoding IL-12 contained in the pharmaceutical composition to be used in combination according to the present invention described in (1) or (2) above is also referred to as the “vaccinia virus to be used in combination”.

The present invention also provides a combination kit comprising the following vaccinia viruses (1) and (2):

-   -   (1) a vaccinia virus comprising a polynucleotide encoding IL-7;         and     -   (2) a vaccinia virus comprising a polynucleotide encoding IL-12.

As used herein, the combination kit is also referred to as the “combination kit according to the present invention” and the vaccinia viruses contained in the combination kit according to the present invention are also referred to as the “vaccinia viruses for the combination kit”.

The combination kit according to the present invention means one or more pharmaceutical compositions to be used to administer two vaccinia viruses: (1) a vaccinia virus comprising a polynucleotide encoding IL-7 and (2) a vaccinia virus comprising a polynucleotide encoding IL-12. When both vaccinia viruses are administered simultaneously, the combination kit can contain the two vaccinia viruses for the combination kit together in a single pharmaceutical composition such as a powder or separately in plural pharmaceutical compositions. The combination kit according to the present invention encompasses a pharmaceutical composition containing two vaccinia viruses: a vaccinia virus comprising a polynucleotide encoding IL-7 and a vaccinia virus comprising a polynucleotide encoding IL-12. When both vaccinia viruses for the combination kit are not simultaneously administered, the combination kit contains the two vaccinia viruses for the combination kit in separate pharmaceutical compositions. For example, the combination kit comprises the two vaccinia viruses for the combination kit in separate pharmaceutical compositions in a single package or in separate pharmaceutical compositions in separate packages. The combination kit according to the present invention may comprise a pharmaceutically acceptable excipient.

In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit is (are) deficient in the function of VGF. In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit is (are) deficient in the function of O1L. In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination or the vaccinia viruses for the combination kit is (are) deficient in the functions of VGF and O1L. The function of VGF and/or O1L may be made deficient in vaccinia virus based on the method described in WO 2015/076422.

In one embodiment, the vaccinia virus carrying IL-7 and IL-12 according to the present invention is vaccinia virus comprising a polynucleotide encoding IL-7 and a polynucleotide encoding L-12 and being deficient in the functions of VGF and O1L.

In one embodiment, the vaccinia virus carrying IL-7 and IL-12 according to the present invention is vaccinia virus of the strain LC16mO comprising a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12 and being deficient in the functions of VGF and O1L.

In one embodiment, the vaccinia virus carrying IL-7 and IL-12 according to the present invention is vaccinia virus comprising a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12, being deficient in the functions of VGF and O1L, and having a deletion in the SCR domains in the B5R extracellular region.

In one embodiment, the vaccinia virus carrying IL-7 and IL-12 according to the present invention is vaccinia virus of the strain LC16mO comprising a polynucleotide encoding IL-7 and a polynucleotide encoding IL-12, being deficient in the functions of VGF and O1L, and having a deletion in the SCR domains in the B5R extracellular region.

In one embodiment, the vaccinia virus to be used in combination or the vaccinia viruses for the combination kit is (are) vaccinia virus comprising a polynucleotide encoding IL-7 and being deficient in the functions of VGF and O1L or vaccinia virus comprising a polynucleotide encoding L-12 and being deficient in the functions of VGF and O1L.

In one embodiment, the vaccinia virus to be used in combination or the vaccinia viruses for the combination kit is (are) vaccinia virus of the strain LC16mO comprising a polynucleotide encoding IL-7 and being deficient in the functions of VGF and O1L or vaccinia virus of the strain LC16mO comprising a polynucleotide encoding IL-12 and being deficient in the functions of VGF and O1L.

In one embodiment, the vaccinia virus to be used in combination or the vaccinia viruses for the combination kit is (are) vaccinia virus comprising a polynucleotide encoding IL-7, being deficient in the functions of VGF and O1L, and having a deletion in the SCR domains in the B5R extracellular region or vaccinia virus comprising a polynucleotide encoding IL-12, being deficient in the functions of VGF and O1L, and having a deletion in the SCR domains in the B5R extracellular region.

In one embodiment, the vaccinia virus to be used in combination or the vaccinia viruses for the combination kit is (are) vaccinia virus of the strain LC16mO comprising a polynucleotide encoding IL-7, being deficient in the functions of VGF and O1L and having a deletion in the SCR domain in the B5R extracellular region or vaccinia virus of the strain LC16mO comprising a polynucleotide encoding IL-12, being deficient in the functions of VGF and O1L, and having a deletion in the SCR domains in the B5R extracellular region.

IL-7 is a secretory protein functioning as an agonist for the IL-7 receptor. It is reported that IL-7 contributes to the survival, proliferation, and differentiation of T cells, B cells, or the like (Sasson et al. (2006) Current Drug Targets 7: 1571-1582). In the present invention, IL-7 encompasses IL-7 occurring naturally and modified forms having the function thereof. In one embodiment, IL-7 is human IL-7. In the present invention, human IL-7 encompasses human IL-7 occurring naturally and modified forms having the function thereof. In one embodiment, human IL-7 is selected from the group consisting of the following (1) to (3):

-   -   (1) a polypeptide comprising the amino acid sequence set forth         in Accession No. NP_000871.1 and having the function of human         L-7;     -   (2) a polypeptide consisting of an amino acid sequence in which         1 to 10 amino acids are deleted from, substituted in, inserted         into, and/or added to the amino acid sequence set forth in         Accession No. NP_000871.1 and having the function of human IL-7;         and     -   (3) a polypeptide comprising an amino acid sequence having a 90%         or more identity with the amino acid sequence set forth in         Accession No. NP_000871.1 and having the function of human L-7.

In relation with this, the function of human IL-7 refers to the effect on the survival, proliferation, and differentiation of human immune cells.

Human L-7 used in the present invention is preferably a polypeptide consisting of the amino acid sequence set forth in Accession No. NP_000871.1.

IL-12 is a heterodimer of the L-12 subunit p40 and the L-12 subunit a. L-12 has been reported to have the function of activating and inducing the differentiation of T cells and NK cells (Lasek et al. (2014) Cancer Immunology Immunotherapy 63: 419-435). In the present invention, IL-12 encompasses L-12 occurring naturally and modified forms having the function thereof. In one embodiment, IL-12 is human L-12. In the present invention, human IL-12 encompasses human L-12 occurring naturally and modified forms having the function thereof. In one embodiment, human IL-12 is selected, as a combination of the human IL-12 subunit p40 and the human IL-12 subunit a, from the group consisting of the following (1) to (3):

-   -   (1) polypeptides comprising (1-a) a polypeptide comprising the         amino acid sequence set forth in Accession No. NP_002178.2,         (1-b) a polypeptide consisting of an amino acid sequence in         which 1 to 10 amino acids are deleted from, substituted in,         inserted into, and/or added to the amino acid sequence set forth         in Accession No. NP_002178.2, or (1-c) a polypeptide comprising         an amino acid sequence having a 90% or more identity with the         amino acid sequence set forth in Accession No. NP_002178.2; and     -   (2-a) a polypeptide comprising the amino acid sequence set forth         in Accession No. NP_000873.2, (2-b) a polypeptide consisting of         an amino acid sequence in which 1 to 10 amino acids are deleted         from, substituted in, inserted into, and/or added to the amino         acid sequence set forth in Accession No. NP_000873.2, or (2-c) a         polypeptide comprising an amino acid sequence having a 90% or         more identity with the amino acid sequence set forth in         Accession No. NP_000873.2, and having the function of human         IL-12;     -   (2) polypeptides comprising:         -   (1-a) a polypeptide consisting of the amino acid sequence             set forth in Accession No. NP 002178.2, and         -   (2-a) a polypeptide comprising the amino acid sequence set             forth in Accession No. NP_000873.2, (2-b) a polypeptide             consisting of an amino acid sequence in which 1 to 10 amino             acids are deleted from, substituted in, inserted into,             and/or added to the amino acid sequence set forth in             Accession No. NP_000873.2, or (2-c) a polypeptide comprising             an amino acid sequence having a 90% or more identity with             the amino acid sequence set forth in Accession No.             NP_000873.2, and having the function of human IL-12; and     -   (3) a polypeptide comprising:         -   (1-a) a polypeptide comprising the amino acid sequence set             forth in Accession No. NP_002178.2, (1-b) a polypeptide             consisting of an amino acid sequence in which 1 to 10 amino             acids are deleted from, substituted in, inserted into,             and/or added to the amino acid sequence set forth in             Accession No. NP_002178.2, or (1-c) a polypeptide comprising             an amino acid sequence having a 90% or more identity with             the amino acid sequence set forth in Accession No.             NP_002178.2, and         -   (2-a) a polypeptide consisting of the amino acid sequence             set forth in Accession No. NP_000873.2, and having the             function of human IL-12.

In relation with this, the function of human IL-12 refers to activating and/or differentiating effects on T cells or NK cells. The IL-12 subunit p40 and the IL-12 subunit a can form IL-12 by direct binding. Moreover, the IL-12 subunit p40 and the IL-12 subunit a can be conjugated via a linker.

Human L-12 used in the present invention is preferably a polypeptide comprising a polypeptide consisting of the amino acid sequence set forth in Accession No. NP_002178.2 and a polypeptide consisting of the amino acid sequence set forth in Accession No. NP_000873.2.

As used herein, “identity” means the value Identity obtained by a search using the NEEDLE program (Needleman et al. (1970) Journal of Molecular Biology 48: 443-453) with the default parameters. The parameters are as follows: Gap penalty=10; Extend penalty=0.5; and Matrix=EBLOSUM62.

The vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit has (have) the oncolytic activity. Examples of methods for evaluating whether or not a test virus has the oncolytic activity include a method for evaluating decrease of the survival rate of cancer cells by the addition of the virus. Examples of cancer cells to be used for the evaluation include the malignant melanoma cell RPMI-7951 (for example, ATCC HTB-66), the lung adenocarcinoma HCC4006 (for example, ATCC CRL-2871), the lung carcinoma A549 (for example, ATCC CCL-185), the small cell lung cancer cell DMS 53 (for example, ATCC CRL-2062), the lung squamous cell carcinoma NCI-H226 (for example, ATCC CRL-5826), the kidney cancer cell Caki-1 (for example, ATCC HTB-46), the bladder cancer cell 647-V (for example, DSMZ ACC 414), the head and neck cancer cell Detroit 562 (for example, ATCC CCL-138), the breast cancer cell JIMT-1 (for example, DSMZ ACC 589), the breast cancer cell MDA-MB-231 (for example, ATCC HTB-26), the esophageal cancer cell OE33 (for example, ECACC 96070808), the glioblastoma U-87MG (for example, ECACC 89081402), the neuroblastoma GOTO (for example, JCRB JCRB0612), the myeloma RPMI 8226 (for example, ATCC CCL-155), the ovarian cancer cell SK-OV-3 (for example, ATCC HTB-77), the ovarian cancer cell OVMANA (for example, JCRB JCRB 1045), the colon cancer cell RKO (for example, ATCC CRL-2577), the colorectal carcinoma HCT 116 (for example, ATCC CCL-247), the pancreatic cancer cell BxPC-3 (for example, ATCC CRL-1687), the prostate cancer cell LNCaP clone FGC (for example, ATCC CRL-1740), the hepatocellular carcinoma JHH-4 (for example, JCRB JCRB0435), the mesothelioma NCI-H28 (for example, ATCC CRL-5820), the cervical cancer cell SiHa (for example, ATCC HTB-35), and the gastric cancer cell Kato III (for example, RIKEN BRC RCB2088). Specific examples of methods for the evaluation that can be used include the method described in Example 3 below.

The vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit produce(s) the IL-7 and/or IL-12 polypeptide(s). Use of the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit markedly increases the antitumor effect by producing the IL-7 and IL-12 polypeptides. The production of IL-7 and IL-12 can be confirmed using a method known in the field, for example, after culturing, with cancer cells, vaccinia virus in which polynucleotides encoding the IL-7 and IL-12 polypeptides are introduced followed by measuring the IL-7 and IL-12 concentrations in the culture supernatant, by immunostaining of cells, by conducting Western blot analysis of the cell lysate, or by measuring the concentrations of IL-7 and IL-12 in the cell lysate. The concentrations of IL-7 and IL-12 can be measured using, for example, Human IL-7 ELISA kit (RayBiotech, Inc.) and Human IL-12 p70 DuoSet ELISA (R&D Systems, Inc.), respectively. Specific examples of methods for evaluating polypeptide concentrations in the culture supernatant or cell lysate that can be used include the method described in Example 4 below. The immunostaining of cells or the Western blot analysis of the cell lysate can be conducted using commercially available antibodies against IL-7 and IL-12.

The polynucleotides encoding IL-7 and IL-12 can be synthesized based on publicly available sequence information using a method of polynucleotide synthesis known in the field. Moreover, once the polynucleotides are obtained; then modified forms having the function of each polypeptide can be generated by introducing mutation into a predetermined site using a method known by those skilled in the art, such as site-directed mutagenesis (Current Protocols in Molecular Biology edition, 1987, John Wiley & Sons Sections 8.1-8.5).

The polynucleotides each encoding IL-7 and IL-12 can be introduced into vaccinia virus by a known technique, such as homologous recombination or site-directed mutagenesis. For example, a plasmid (also referred to as transfer vector plasmid DNA) in which the polynucleotide(s) is (are) introduced into the nucleotide sequence at the site desired to be introduced can be made and introduced into cells infected with vaccinia virus. The region in which the polynucleotides each encoding IL-7 and IL-12, foreign genes, are introduced is preferably a gene region that is inessential for the life cycle of vaccinia virus. For example, in a certain aspect, the region in which IL-7 and/or L-12 is (are) introduced may be a region within the VGF gene in vaccinia virus deficient in the VGF function, a region within the O1L gene in vaccinia virus deficient in the O1 function, or a region or regions within either or both of the VGF and O1L genes in vaccinia virus deficient in both VGF and O1 functions. In the above, the foreign gene(s) can be introduced so as to be transcribed in the direction same as or opposite to that of the VGF and O1L genes.

Methods for introducing transfer vector plasmid DNA into cells are not particularly limited, but examples of methods that can be used include the calcium phosphate method and electroporation.

When introducing the polynucleotides each encoding IL-7 and IL-12, which are foreign genes, a suitable promoter(s) can be operably linked in the upstream of the foreign gene(s). In this way, the foreign gene(s) in the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit can be linked to a promoter that can promote expression in tumor cells. Examples of such a promoter include PSFJ1-10, PSFJ2-16, the p7.5K promoter, the p11K promoter, the T7.10 promoter, the CPX promoter, the HF promoter, the H6 promoter, and the T7 hybrid promoter.

In one embodiment, the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit has (have) no drug-selection marker gene.

The vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit may be expressed and/or proliferated by infecting host cells with the vaccinia virus(es) and culturing the infected host cells. Vaccinia virus may be expressed and/or proliferated by a method known in the field. Host cells to be used to express or proliferate the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit are not particularly limited, as long as the vaccinia virus according to the present invention, the vaccinia virus carrying L-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit can be expressed and proliferated. Examples of such host cells include animal cells such as BS-C-1, A549, RK13, HTK-143, Hep-2, MDCK, Vero, HeLa, CV-1, COS, BHK-21, and primary rabbit kidney cells. BS-C-1 (ATCC CCL-26), A549 (ATCC CCL-185), CV-1 (ATCC CCL-70), or RK13 (ATCC CCL-37) may be preferably used. Culture conditions for the host cells, for example, temperature, pH of the medium, and culture time, are selected as appropriate.

Methods for producing the vaccinia virus according to the present invention, the vaccinia virus carrying L-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, and the vaccinia viruses for the combination kit may comprise the steps of: infecting host cells with the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit; culturing the infected host cells; and expressing the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit; and optionally collecting and preferably purifying the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the vaccinia virus to be used in combination, or the vaccinia viruses for the combination kit. Methods that can be used for the purification include DNA digestion with Benzonase, sucrose gradient centrifugation, Iodixanol density gradient centrifugation, ultrafiltration, and diafiltration.

Pharmaceutical Composition According to the Present Invention

The pharmaceutical compositions according to the present invention include a pharmaceutical composition comprising the vaccinia virus according to the present invention or the vaccinia virus carrying IL-7 and IL-12 according to the present invention, and a pharmaceutically acceptable excipient. The pharmaceutical compositions according to the present invention also include the pharmaceutical composition to be used in combination according to the present invention. In one embodiment, the pharmaceutical composition to be used in combination according to the present invention comprises a pharmaceutically acceptable excipient.

The pharmaceutical compositions according to the present invention may be prepared by a method usually used in the field, using an excipient usually used in the field, that is, a pharmaceutical excipient, a pharmaceutical carrier, or the like. Examples of the dosage form of such pharmaceutical compositions include parenteral formulations such as injections and infusions and these can be administered by intravenous administration, subcutaneous administration, intratumoral administration, or the like. In the formulation, excipients, carriers, or additives suitable for these dosages form may be used as long as these are pharmaceutically acceptable.

The effective dose varies according to the severity of the symptom or the age of the patient, the dosage form of the formulation to be used, or the titer of the virus, but, for example, approximately 10²-10¹⁰ plaque-forming units (PFU) may be used as an effective dose of a single virus, as a combined effective dose of 2 viruses in a combination kit, or as a combined effective dose of 2 viruses administered in combination. Two viruses in a combination kit may be used, for example, at a dosage ratio of approximately 1:10 to 10:1, approximately 1:5 to 5:1, approximately 1:3 to 3:1, approximately 1:2 to 2:1, or about 1:1.

Application for Preventing or Treating Cancer

The pharmaceutical compositions according to the present invention can be used as a prophylactic or therapeutic agent for cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer.

The present invention includes a pharmaceutical composition for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer, the composition comprising the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, or the vaccinia virus to be used in combination.

The present invention includes a combination kit for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer, the combination kit comprising each of the vaccinia viruses for the combination kit.

Moreover, the present invention includes a method for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer, the method comprising the step of administering the vaccinia virus according to the present invention and/or the vaccinia virus carrying IL-7 and IL-12 according to the present invention to a subject (for example, a patient) in need of the prevention or treatment of cancer.

Moreover, the present invention includes a method for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer, the method comprising the step of administering the following (1) and (2) to a subject (for example, a patient) in need of the prevention or treatment of cancer:

-   -   (1) a vaccinia virus comprising a polynucleotide encoding IL-7;         and     -   (2) a vaccinia virus comprising a polynucleotide encoding IL-12.

The two vaccinia viruses may be administered to a subject simultaneously, separately, continuously, or at intervals.

Moreover, the present invention includes the vaccinia virus according to the present invention and the vaccinia virus carrying IL-7 and IL-12 according to the present invention, for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer.

The present invention includes the vaccinia virus selected from the following (1) or (2), for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer:

-   -   (1) a vaccinia virus comprising a polynucleotide encoding IL-7,         for preventing or treating cancer in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-12; or     -   (2) a vaccinia virus comprising a polynucleotide encoding IL-12,         for preventing or treating cancer in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-7.

Furthermore, the present invention includes use of the vaccinia virus according to the present invention and/or the vaccinia virus carrying L-7 and IL-12 according to the present invention, for the manufacture of a pharmaceutical composition for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer.

The present invention includes use of a vaccinia virus selected from the following (1) or (2), for the manufacture of a pharmaceutical composition for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer:

-   -   (1) use of a vaccinia virus comprising a polynucleotide encoding         IL-7, for the manufacture of a pharmaceutical composition for         preventing or treating cancer to be used in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-12; or     -   (2) use of a vaccinia virus comprising a polynucleotide encoding         IL-12, for the manufacture of a pharmaceutical composition for         preventing or treating cancer to be used in combination with a         pharmaceutical composition comprising a vaccinia virus         comprising a polynucleotide encoding IL-7.

Furthermore, the present invention includes use of a vaccinia virus comprising a polynucleotide encoding IL-7 and a vaccinia virus comprising a polynucleotide encoding IL-12, for the manufacture of a combination kit for preventing or treating cancer, for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer.

As used herein, “for preventing” is used synonymously with “for use in preventing” and “for treating” is used synonymously with “for use in treating”.

The pharmaceutical compositions or the combination kit according to the present invention may be used in combination with various therapeutic agents having efficacy for cancer for example, a cancer selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer and gastric cancer. The combination use may be performed by simultaneous administration, or separate administration continuously or at the desired interval. When administered simultaneously, the pharmaceutical compositions according to the present invention may be administered as a combined drug or as formulations formulated separately.

Cancers that the vaccinia virus according to the present invention, the vaccinia virus carrying IL-7 and IL-12 according to the present invention, the pharmaceutical compositions according to the present invention, the combination kit according to the present invention, the method for preventing or treating cancer according to the present invention, or use according to the present invention is (are) applied to include metastatic cancers to an organ, for example, a lymph node, liver, or the like, besides the primary lesion.

The present invention has been generally described, but specific Examples for reference to get further understanding of the present invention are provided below. These Examples are for the illustration purpose, but not intended to limit the present invention.

EXAMPLES

Experiments with a commercially available kit or a reagent were conducted according to attached protocols unless otherwise specified.

Example 1: Construction of Transfer Vector Plasmid DNA

Transfer vector plasmid DNAs to be used for generating recombinant vaccinia viruses by homologous recombination were prepared as follows:

(1) Construction of pTN-VGF-P-DsRed Transfer Vector Plasmid DNA

The pUC19-VGF vector was prepared according to WO 2015/076422. More specifically, genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as template and the pUC19 vector (product cord: 54357) from Invitrogen was used for the preparation of the pUC19-VGF vector. The prepared pUC19-VGF vector was digested with the restriction enzyme AccI and then the ends were blunted. The transfer vector plasmid DNA was constructed by inserting a DNA fragment (SEQ ID NO: 22) containing the p7.5k promoter and a DsRed fragment in this cleavage site. The constructed plasmid DNA was named pTN-VGF-P-DsRed.

(2) Construction of pTN-VGF-SP-IL12 and pTN-VGF-SP-IL7 Transfer Vector Plasmid DNAs

A BFP gene region was amplified with two primers (SEQ ID NO: 1 and SEQ ID NO: 2) using DNA of the pTagBFP-N vector (FP172, Evrogen) as template. The PCR product was digested with the restriction enzymes SfiI and EcoRI and cloned into the same restriction enzyme sites in the pTK-SP-LG vector (WO 2015/076422 with the proviso that genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as template and the pUC19 vector (product cord: 54357) from Invitrogen was used; and, for the pVNC 110-Luc/IRES/EGFP plasmid, pVNC110-Luc/IRES/EGFP described in WO 2011/125469 was used.) to construct pTK-SP-BFP in which BFP is linked to a synthetic vaccinia virus promoter (Hammond et al. (1997) Journal of Virological Methods 66: 135-138). Next, pTK-SP-BFP was digested with the restriction enzymes SphI and EcoRI and the ends were blunted. The resulting DNA fragment was cloned into the pUC19-VGF vector at a site generated by digesting the plasmid with the restriction enzyme AccI and blunting the ends to construct pTN-VGF-SP-BFP (FIG. 1). Next, a polynucleotide encoding human IL-12 (a polynucleotide containing the human IL-12 subunit p40, an internal ribosomal entry site, and the human IL-12 subunit c; SEQ ID NO: 7) and a polynucleotide (SEQ ID NO: 8) encoding human IL-7 (each polynucleotide contains the restriction enzyme site accggtcgccacc (SEQ ID NO: 16) at the 5′ side and the restriction enzyme site gctagcgaattc (SEQ ID NO: 17) at the 3′side.) were digested with the restriction enzymes AgeI and NheI. Each of the polynucleotide fragments was cloned into the same restriction enzyme site in pTN-VGF-SP-BFP to construct the transfer vector plasmid DNA. The constructed plasmid DNAs were named pTN-VGF-SP-IL12 and pTN-VGF-SP-IL7, respectively.

(3) Construction of pTN-O1L-SP-BFP, pTN-O1L-SP-LacZ, pTN-O1L-SP-IL12, and pTN-O1L-SP-IL 7 Transfer Vector Plasmid DNAs

In the same way as (2) above, pTK-SP-BFP was digested with the restriction enzymes SphI and EcoRI and the DNA fragment obtained by blunting the ends was cloned into the pUC19-O1L vector (WO 2015/076422 with the proviso that, like the preparation of the pUC19-VGF vector, genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as template and the pUC19 vector (product cord: 54357) from Invitrogen was used; and the O1L gene region was inserted into the XbaI site in the pUC19 vector.) at a site generated by digesting the plasmid with the restriction enzyme XbaI and blunting the ends to construct the transfer vector plasmid DNA (FIG. 1). The prepared plasmid DNA was named pTN-O1L-SP-BFP. Next, a polynucleotide (SEQ ID NO: 9) containing the Escherichia coli LacZ gene with codons optimized for human, a polynucleotide (SEQ ID NO: 7) encoding human IL-12, and a polynucleotide (SEQ ID NO: 8) encoding human IL-7 were digested with the restriction enzymes AgeI and NheI. Each of the polynucleotide fragments encoding LacZ, IL-12, or IL-7 was cloned into the same restriction enzyme sites (the AgeI and NheI sites) in the pTN-O1L-SP-BFP vector to construct the transfer vector plasmid DNA. The constructed plasmid DNAs were named pTN-O1L-SP-LacZ, pTN-O1L-SP-IL12, and pTN-O1L-SP-IL7, respectively.

(4) Construction of pTN-DsRed (B5R-) and pTN-B5RΔ1-4 Transfer Vector Plasmid DNAs

The B4R gene region was amplified with two primers (SEQ ID NO: 3 and SEQ ID NO: 4) using DNA of pB5R (WO 2011/125469, with the proviso that genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as template) as template. Moreover, the DsRed gene region was amplified with two primers (SEQ ID NO: 5 and SEQ ID NO: 6) using DNA of pDsRed-Express-N1 (Clontech Laboratories, Inc.) as template. The former PCR product was digested with the restriction enzymes NotI and FspI and the latter PCR product was digested with the restriction enzymes FspI and MfeI. These two DNA fragments were cloned into pB5R digested with the restriction enzymes NotI and MfeI to construct the transfer vector plasmid DNA. The prepared plasmid DNA was named pTN-DsRed (B5R-). Meanwhile, pB5R was digested with the restriction enzymes NotI and NspI or the restriction enzymes NspI and SacI. These two DNA fragments were cloned into pB5R digested with the restriction enzymes NotI and SacI to construct the transfer vector plasmid DNA. The prepared plasmid DNA was named pTN-B5RΔ1-4. pTN-B5RΔ1-4 encodes the B5R protein with the deletion of four SCR domains. The amino acid sequence thereof is the sequence set forth in SEQ ID NO: 18.

Example 2: Construction of Genetically Engineered Vaccinia Virus

A recombinant vaccinia virus (referred to as LC16mO VGF-SP-LucGFP/O1L-p7.5-DsRed) deficient in the functions of VGF and O1L was prepared from the vaccinia virus strain LC16mO. This recombinant vaccinia virus was sequenced with a next-generation sequencer PacBio RSII (Pacific Biosciences of California, Inc.) and the virus genome was reconstituted from the obtained sequence information using the Sprai [BMC GENOMICS. 2014 Aug. 21, 15:699.] software to determine the nucleotide sequence, which is the nucleotide sequence set forth in SEQ ID NO: 21. Moreover, loop sequences were added to both ends of the nucleotide sequence and the loop sequences at both ends were the nucleotide sequences set forth in SEQ ID NOs: 19 or 20.

(1) The recombinant vaccinia viruses having the virus genome illustrated in FIG. 2 were collected. The virus collecting procedure is specifically described below. CV1 cells (ATCC CCL-70) or RK13 cells (ATCC CCL-37) cultured to 80% confluent in 6 well dishes were infected with LC16mO VGF-SP-LucGFP/O1L-p7.5-DsRed at a Multiplicity of infection (MOI)=0.02-0.1 and the virus was allowed to be adsorbed at room temperature for 1 hour. pTN-O1L-SP-BFP constructed in Example 1 (3) was mixed with FuGENE® HD Transfection Reagent (Roche), added to cells according to the manual to be incorporated into the cells and the cells were cultured at 5% CO₂ and 37° C. for 2-5 days. The cells were freeze-thawed, sonicated, and diluted with Opti-MEM (Invitrogen) so as to obtain single plaques by the following operation. 100 μL of the resulting diluted fluid was added to inoculate BS-C-1 cells (ATCC CCL-26) or RK13 cells cultured to sub-confluent in 6 well dishes. 2 mL of the Eagle MEM medium (NISSUI, 05900) containing 0.8% methylcellulose (Wako Pure Chemical Industries, Ltd., 136-02155), 5% fetal bovine serum, 0.225% sodium bicarbonate (Wako Pure Chemical Industries, Ltd., 195-16411), and GlutaMAX™ Supplement I (GIBCO, 35050-061) was added and the cells were cultured at 5% CO₂ and 37° C. for 2-5 days. The medium was removed and plaques, as indicated by the BFP expression, were scraped off with the pointing end of a tip to be suspended into Opti-MEM. This operation was repeated three times or more with BS-C-1 or RK13 cells to purify plaques and collect the virus plaques (In this Example, the procedure up to this point is hereinafter referred to as the “collecting”.). The plaques were suspended into Opti-MEM and sonicated. Genomic DNA was extracted from 200 μL of the sonicated solution using High Pure Viral Nucleic Acid Kit (Roche) according to the manual and screened by PCR. PCR was performed for VGF with the two primers (SEQ ID NO: 10 and SEQ ID NO; 11), for O1L with the two primers (SEQ ID NO: 12 and SEQ ID NO: 13), and for B5R with the two primers (SEQ ID NO: 14 and SEQ ID: NO 15). Among the clones from which an expected size of PCR product was detected, a virus clone for which the correct nucleotide sequence of the PCR product was confirmed by direct sequencing (referred to as LC16mO VGF-SP-LucGFP/O1L-SP-BFP. FIG. 2) was selected and proliferated with A549 (ATCC CCL-185) or RK13 cells and then the virus titer was measured with RK13 cells. Using LC16mO VGF-SP-LucGFP/O1L-SP-BFP and pTN-DsRed (B5R-) prepared in Example 1 (4), the recombinant virus, as indicated by the DsRed expression instead of the BFP expression, was collected in a way same as that described above. The virus was named LC16mO Δ-DsRed VGF-SP-LucGFP/O1L-SP-BFP (FIG. 2).

(2) A recombinant virus having the deletion of the 4 SCR domains in the B5R protein was collected. Specifically, using LC16mO Δ-DsRed VGF-SP-LucGFP/O1L-SP-BFP prepared in Example 2 (1) and pTN-B5RΔ1-4 constructed in Example 1 (4), the recombinant virus, as indicated by the disappearance of DsRed expression instead of the BFP expression, was collected in a way same as that in Example 2 (1). The virus was named LC16mO ΔSCR VGF-SP-LucGFP/O1L-SP-BFP (FIG. 2). Moreover, using the prepared LC16mO ΔSCR VGF-SP-LucGFP/O1L-SP-BFP and pTN-VGF-P-DsRed constructed in Example 1 (1), the recombinant virus, as indicated by the DsRed expression instead of the BFP expression, was collected in a way same as that in Example 2 (1). The virus is named LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-BFP (FIG. 2). Next, using the obtained LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-BFP and pTN-O1L-SP-LacZ constructed in Example 1 (3), the recombinant virus, as indicated by the disappearance of BFP expression instead of the BFP expression, was collected in a way same as that in Example 2 (1). The virus was named LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-LacZ (FIG. 2).

(3) The SCR region-deleted recombinant vaccinia viruses having the virus genome illustrated in FIG. 3 and expressing a therapeutic gene and a marker gene were collected. Specifically, using each of LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-LacZ prepared in Example 2 (2) and the transfer vector plasmid DNAs (pTN-VGF-SP-IL12 and pTN-VGF-SP-IL7) constructed in Example 1 (2), each of the recombinant viruses, as indicated by the disappearance of DsRed expression instead of the BFP expression, was collected in a way same as that in Example 2 (1). The viruses were named LC16mO ΔSCR VGF-SP-IL12/O1L-SP-LacZ (hereinafter, referred to as the “hIL12-carrying vaccinia virus”.) and LC16mO ΔSCR VGF-SP-IL7/O1L-SP-LacZ (hereinafter, referred to as the “hIL7-carrying vaccinia virus”.) (FIG. 3). For purification, A549 or RK13 cells were infected with each of the recombinant viruses. The cells were cultured at 5% CO₂ and 37° C. for 2-5 days and then the infected cells were harvested. The cells were freeze-thawed and sonicated. The viruses were purified by density gradient centrifugation using OptiPrep (Axis-Shield Diagnostics Ltd.). The virus titer of each virus was measured with RK13 cells.

(4) The SCR domain-deleted recombinant vaccinia virus having the virus genome illustrated in FIG. 4 and expressing a polynucleotide encoding human IL-7 and a polynucleotide encoding human IL-12 was collected.

(4-1) Specifically, using LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-BFP prepared in Example 2 (2) and the transfer vector plasmid DNA pTN-VGF-SP-IL12 constructed in Example 1 (2), each of the recombinant viruses, as indicated by the disappearance of DsRed expression instead of the BFP expression, was collected in a way same as that in Example 2 (1). The virus was named LC16mO ΔSCR VGF-SP-IL 12/O1L-SP-BFP.

(4-2) Next, using LC16mO ΔSCR VGF-SP-IL12/O1L-SP-BFP prepared in Example 2 (4-1) and the transfer vector plasmid DNA pTN-O1L-SP-IL7 constructed in Example 1 (3), each of the recombinant viruses, as indicated by the disappearance of BFP expression instead of the BFP expression, was collected in a way same as that in Example 2 (1). The virus was named LC16mO ΔSCR VGF-SP-IL12/O1L-SP-IL7 (hereinafter, in Examples below, also referred to as the “hiL12 and hIL7-carrying vaccinia virus”.) (FIG. 4). Each recombinant virus was purified by the method in Example 2 (3) and then the virus titer of each virus was measured with RK13 cells.

Example 3: Oncolytic Property of Genetically Engineered Vaccinia Virus

The ability of the hIL12 and hIL7-carrying vaccinia virus prepared in Example 2 to lyse various human cancer cells (ability to kill cells) was evaluated. Moreover, the ability of a combined mixture of 2 viruses, the hIL12-carrying vaccinia virus and the hIL7-carrying vaccinia virus prepared in Example 2, to lyse various human cancer cells was similarly evaluated.

Specifically, 100 μL each of the cells suspended at 1×10⁴ cells/mL in a medium (a medium described below containing 10% fetal bovine serum (GE Healthcare) and 1% penicillin-streptomycin (Life Technologies)) was first added into 96 well plates (AGC TECHNO GLASS CO., LTD.). After culturing overnight, 1) the hIL12 and hIL7-carrying vaccinia virus and 2) a mixture combining 1:1 concentrations of the hIL12-carrying vaccinia virus and the hIL7-carrying vaccinia virus (hereinafter, referred to as the “mixture of hIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus”) were each diluted with Opti-MEM (Life Technologies) at 5×10⁴ PFU/mL, 5×10⁵ PFU/mL, and 5×10⁶ PFU/mL, respectively. 20 μL each of the virus solutions was added to each well to infect cells at MOI=1.0, 10, or 100. As control, wells with no cells and wells to which Opti-MEM was added instead of virus (MOI=0) were prepared. The cells were then cultured for 5 days in a CO₂ incubator set to a CO₂ concentration of 5% and at 37° C. The cell survival rate on Day 5 was measured with CellTiter-Glo Luminescent Cell Viability Assay (Promega KK.). Specifically, according to the protocol of the assay kit, 100 μL each of CellTiter-Glo Reagent was added to each well and left to stand for 30 minute, the total amount was then transferred into 96 well black plates (Corning Incorporated), and the strength of luminescence in each well was measured with EnSpire (PerkinElmer Inc.). For the calculation of the cell survival rate in each well, the value of wells in which no cells have seeded was defined as 0% survival and the value of wells in which cells have seeded and no virus was added was defined as 100% survival.

The evaluated cells were the malignant melanoma cell RPMI-7951 (ATCC HTB-66), the lung adenocarcinoma HCC4006 (ATCC CRL-2871), the lung carcinoma A549 (ATCC CCL-185), the small cell lung cancer cell DMS 53, the lung squamous cell carcinoma NCI-H226 (ATCC CRL-5826), the kidney cancer cell Caki-1 (ATCC HTB-46), the bladder cancer cell 647-V (DSMZ ACC 414), the head and neck cancer cell Detroit 562 (ATCC CCL-138), the breast cancer cell JIMT-1 (DSMZ ACC 589), the breast cancer cell MDA-MB-231 (ATCC HTB-26), the esophageal cancer cell OE33 (ECACC 96070808), the glioblastoma U-87MG (ECACC 89081402), the neuroblastoma GOTO (JCRB JCRB0612), the myeloma RPMI 8226 (ATCC CCL-155), the ovarian cancer cell SK-OV-3 (ATCC HTB-77), the ovarian cancer cell OVMANA (JCRB JCRB 1045), the colon cancer cell RKO (ATCC CRL-2577), the colorectal carcinoma HCT 116, the pancreatic cancer cell BxPC-3 (ATCC CRL-1687), the prostate cancer cell LNCaP clone FGC (ATCC CRL-1740), the hepatocellular carcinoma JHH-4 (JCRB JCRB0435), the mesothelioma NCI-H28 (ATCC CRL-5820), the cervical cancer cell SiHa (ATCC HTB-35) and the gastric cancer cell Kato III (RIKEN BRC RCB2088).

The media used were RPMI1640 medium (Sigma-Aldrich Co. LLC., R8758) for RPMI-7951, HCC4006, DMS 53, NCI-H226, Caki-1, 647-V, Detroit 562, JIMT-1, OE33, U-87MG, GOTO, RPMI8226, SK-OV-3, OVMANA, RKO, HCT 116, BxPC-3, LNCaP clone FGC, JHH-4, NCI-H28, and Kato III, DMEM medium (Sigma-Aldrich Co. LLC., D6429) for A549 and MDA-MB-231, and EMEM medium (ATCC 30-2003) for SiHa. The results were as illustrated in FIGS. 5A to 5D. In relation with this, the effects of the hiL12 and hIL7-carrying vaccinia virus were illustrated separately in FIGS. 5A and 5B and the effects of the mixture of hIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus were illustrated separately in FIGS. 5C and 5D.

As a result, the hiL12 and hIL7-carrying vaccinia virus was shown to have the ability to kill cells in all examined human cancer cells (FIGS. 5A and 5B). Moreover, the mixture of hIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus was also shown to have the ability to kill cells in all examined human cancer cells (FIGS. 5C and 5D). In FIGS. 5A to 5D, the oncolytic properties at MOI=0, 1, 10, and 100 are shown from the left in this order for each cell line.

Example 4: Protein Production from Cancer Cells Infected with Genetically Engineered Vaccinia Virus

When cancer cells were infected with the hiL12 and hIL7-carrying vaccinia virus, the concentrations of the human IL-7 protein and the human IL-12 protein produced by cancer cells were measured. Furthermore, the concentrations of the human IL-7 protein and the human IL-12 protein produced by cancer cells when cancer cells were infected with the mixture of hIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus were similarly measured.

The measurement of the human IL-7 protein was conducted as follows. Specifically, first, 100 μL of SK-OV-3 ovarian cancer cells suspended at 1×10⁴ cells/mL in RPMI1640 medium containing 10% fetal bovine serum and the 1% penicillin-streptomycin was seeded into 96 well plates. After culturing overnight, 1) the hiL12 and hIL7-carrying vaccinia virus or 2) the mixture of hIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus was prepared in Opti-MEM and 20 μL each was added to infect the cells at MOI=1.0. The cells were then cultured for 24 hours in a CO₂ incubator set at a CO₂ concentration of 5% and 37° C. and the culture supernatant was collected. The concentration of the protein contained in the culture supernatant was measured with the ELISA kit listed in Table 1 and EnSpire.

The measurement of the human IL-12 protein was conducted as follows. Specifically, first, 100 μL of SK-OV-3 ovarian cancer cells suspended at 1×10⁵ cells/mL in RPMI1640 medium containing 10% fetal bovine serum and the 1% penicillin-streptomycin was seeded into 96 well plates. After culturing overnight, 1) the hiL12 and hIL7-carrying vaccinia virus or 2) the mixture of hIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus was prepared in Opti-MEM and 20 μL each was added to infect the cells at MOI=1.0. The cells were then cultured for 48 hours in a CO₂ incubator set at a CO₂ concentration of 5% and 37° C. and the culture supernatant was collected. The concentration of the protein contained in the culture supernatant was measured with the ELISA kit listed in Table 1 and EnSpire.

TABLE 1 ELISA kit used in Example 4 Protein ELISA kit Provider Human IL-7 Human IL-7 ELISA kit RayBiotech, Inc. Human IL-12 Human IL-12 p70 DuoSet R&D Systems, Inc. ELISA

As a result, it was shown that the human IL-12 protein and the human IL-7 protein were produced from the cells to which the hiL12 and hIL7-carrying vaccinia virus was added and the cells to which the mixture of hIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus was added (Tables 2-1 and 2-2).

TABLE 2-1 Concentration of human IL-12 protein in culture supernatant Human IL-12 protein Genetically engineered vaccinia virus concentration (ng/mL) hIL12 and hIL7-carrying vaccinia virus 31.45 Mixture of hIL12-carrying vaccinia virus 17.74 and hIL7-carrying vaccinia virus

TABLE 2-2 Concentration of human IL-7 protein in culture supernatant Human IL-7 protein Genetically engineered vaccinia virus concentration (ng/mL) hIL12 and hIL7-carrying vaccinia virus 0.86 Mixture of hIL12-carrying vaccinia virus 0.60 and hIL7-carrying vaccinia virus

Example 5: Construction of Transfer Vector Plasmid DNA Carrying Polynucleotide Encoding Murine IL-12 and Construction of Recombinant Vaccinia Virus Carrying Polynucleotide Encoding Murine IL-12

(1) The transfer vector plasmid DNA pTN-VGF-SP-mIL12 was constructed according to the method described in Example 1 (2). Instead of the polynucleotide (SEQ ID NO: 7) encoding human IL-12 in the method described in Example 1 (2), a polynucleotide encoding murine IL-12 (a polynucleotide containing the murine IL-12 subunit p40, an internal ribosomal entry site, and the murine IL-12 subunit c. SEQ ID NO: 23) was used and this polynucleotide fragment was cloned into pTN-VGF-SP-BFP.

(2) The transfer vector plasmid DNA pTN-O1L-SP-Luc2 was constructed according to the method described in Example 1 (3). Instead of the polynucleotide (SEQ ID NO: 9) containing the Escherichia coli LacZ gene in the method described in Example 1 (3), a polynucleotide (100-1752 in Accession No. DQ188840) encoding the luciferase Luc2 gene was used and this polynucleotide fragment was cloned into pTN-O1L-SP-BFP.

(3) The recombinant virus was collected according to the method in Example 2 (2). In the method in Example 2 (2), LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-BFP and pTN-O1L-SP-Luc2 prepared in Example 5 (2) instead of pTN-O1L-SP-LacZ were used. The virus was named LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-Luc2 (hereinafter, this virus is also referred to as the “control vaccinia virus”.).

(4) The recombinant virus was collected according to the method in Example 2 (3). Instead of LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-LacZ and pTN-VGF-SP-IL12 in the method in Example 2 (3), respectively, LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-Luc2 prepared in Example 5 (3) and pTN-VGF-SP-mIL12 prepared in Example 5 (1) were used. The virus was named LC16mO ΔSCR VGF-SP-mIL12/O1L-SP-Luc2 (hereinafter, also referred to as the “mL 12-carrying vaccinia virus”.).

(5) The recombinant virus was collected according to the method in Example 2 (4-1). LC16mO ΔSCR VGF-p7.5-DsRed/O1L-SP-BFP and pTN-VGF-SP-mIL12 prepared in Example 5 (1) instead of pTN-VGF-SP-IL12 in the method in Example 2 (4-1) were used. The virus was named LC16mO ΔSCR VGF-SP-mIL12/O1L-SP-BFP.

Furthermore, the recombinant virus was collected according to the method in Example 2 (4-2). Instead of LC16mO ΔSCR VGF-SP-IL12/O1L-SP-BFP in the method in Example 2 (4-2), LC16mO ΔSCR VGF-SP-mIL12/O1L-SP-BFP prepared as described above and pTN-O1L-SP-IL7 were used. The virus was named LC16mO ΔSCR VGF-SP-mIL12/O1L-SP-IL7 (hereinafter, also referred to as the “mIL12 and hIL7-carrying vaccinia virus”.).

Example 6: Antitumor Effect of Genetically Engineered Vaccinia Virus in Cancer-Bearing Humanized Mouse

The in vivo antitumor effect of the hIL12 and hIL7-carrying vaccinia virus was evaluated using humanized mice (mice in which the immune system is replaced with human immune cells by introducing human hematopoietic stem cells into a severely immunodeficient mouse) into which human cancer cells are transplanted.

Specifically, in order to generate humanized mice, 3×10⁴ hematopoietic stem cells (Lonza) derived from human umbilical cord blood were first introduced by injecting via a tail vein into NOG mice (NOD/Shi-scidIL-2RyKO Jic, female, 6 week-old, CLEA Japan, Inc.) irradiated with X-ray at a strength of 2.0 grays using an X-ray irradiation apparatus. 13 weeks after the introduction, 100 μL of the human lung cancer cell NCI-H1373 (ATCC CRL-5866) suspended at 3×10⁷ cells/mL in PBS was transplanted by injecting the cells subcutaneously in the right back side of the mice. The tumor diameter was measured with a caliper after cancer cell transplantation and the mice were assigned to groups so that the mean tumor volumes of the groups (minor axis mm×minor axis mm×major axis mm×0.52) will become 37 mm³ to 47 mm³. On the same day, 20 μL of the hiL12 and hIL7-carrying vaccinia virus diluted to a concentration of 1.0×10⁸ PFU/mL in PBS was injected into tumor (referred to as the “hLl12 and hIL7-carrying VV treated group” in the Table). 20 μL of PBS was administered into tumor in a group, which was referred to as the vehicle (PBS) treated group. The tumor diameter of each mouse was measured with a caliper every 2-4 days, the tumor volume was calculated based on the formula above, and the percent (%) change in tumor volume on the 14th day after the virus administration was calculated by the following formula for each individual (n=7-8):

Percent (%) change in tumor volume on 14th day after virus administration=100(%)×tumor volume (mm³) on 14th day after virus administration/tumor volume (mm³) on day of virus administration.

The tumor regression effect was determined to be positive when the mean percent (%) change in tumor volume on the 14th day after the virus administration of each group was less than 100 and a significant difference was observed (the significant difference was defined when p value <0.05) between the tumor volume on the 14th day after the virus administration and the tumor volume on the day of the virus administration in each group when tested by the paired t-test.

In this Example, the control vaccinia virus (2×10⁶ PFU/individual), the hIL12-carrying vaccinia virus (2×10⁶ PFU/individual), or the hIL7-carrying vaccinia virus (2×10⁶ PFU/individual) (referred to as the “control VV treated group”, the “hIL12-carrying VV treated group”, and the “hIL7-carrying VV treated group” in the Table.) were used with the same injection volume (20 μL) and the same dilution solution (PBS) as a virus compared with the hIL12 and hIL7-carrying vaccinia virus (2×10⁶ PFU/individual).

As a result, the hiL12 and hIL7-carrying vaccinia virus treated group exhibited a mean percent change in tumor volume on the 14th day after the virus administration of less than 100%. Furthermore, there was a significant difference observed between the tumor volume on the 14 days after the virus administration and the tumor volume on the day of virus administration examined by the paired t-test and therefore the tumor regression effect was determined to be positive (Table 3). Thus, the administration of the hiL12 and hIL7-carrying vaccinia virus was shown to have the tumor regression effect. On the other hand, the tumor regression effect was not confirmed in the group receiving either of the hIL12-carrying vaccinia virus or the hIL7-carrying vaccinia virus (Table 3).

TABLE 3 Percent (%) change in tumor volume in cancer-bearing humanized mouse with the hIL12 and hIL7-carrying vaccinia virus p value (tumor volume on 14th day after virus Percent (%) change administration in tumor volume on and tumor volume 14th day after on day of virus administration administration were Mean +/− examined by the Experimental group n standard error paired t-test) Vehicle (PBS) treated 7 653 ± 43 <0.05 group Control VV treated group 7 187 ± 39 0.09 hIL7-carrying VV treated 8 199 ± 33 <0.05 group hIL12-carrying VV 8 140 ± 29 0.40 treated group hIL12 and hIL7-carrying 8 61 ± 6 <0.05 VV treated group

Example 7: Complete Remission-Inducing Effect of Genetically Engineered Vaccinia Virus in Syngeneic Cancer-Bearing Mouse Models

(1) Effect of mIL12 and hIL7-Carrying Vaccinia Virus

The complete remission-inducing effect of the mIL12 and hIL7-carrying vaccinia virus in vivo was evaluated using mice subcutaneously transplanted with syngeneic murine cancer cell line (syngeneic cancer-bearing mice). Since human IL-12 is known to have no effect on murine immune cells, a genetically engineered vaccinia virus carrying a polynucleotide encoding murine IL-12 instead of the polynucleotide encoding human IL-12 (prepared in Example 5) was used.

Specifically, 50 μL of the murine lung cancer cell LL/2 (LLC1) (ATCC CRL-1642) (hereinafter referred to as LLC1) prepared at 4×10⁶ cells/mL in PBS was first subcutaneously transplanted in the right flank of C57BL/6J mice (male, 5-7 week-old, CHARLES RIVER LABORATORIES JAPAN, INC.). The tumor volume was calculated in a way same as that in Example 6 and mice were assigned to groups so that the mean tumor volume of each group will become 50 mm³ to 60 mm³. On the next day, 30 μL of the mIL12 and hIL7-carrying vaccinia virus diluted to a concentration of 6.7×10⁸ PFU/mL in PBS was intratumorally injected in 12 mice (2×10⁷ PFU, referred to as the “mIL12 and hIL7-carrying VV treated group” in the Table.). Similar intratumoral injection of the virus was conducted 2 days and 4 days after the first administration. 30 μL of PBS instead of the virus was intratumorally administered in a group, which was referred to as the vehicle (PBS) treated group.

The tumor diameter was measured with a caliper twice a week and the tumor volume was calculated. Absence of tumor observed by palpation on 27th day after the first administration of the virus was defined as complete remission and the number of individuals achieved complete remission was counted. Groups reached a mean tumor volume above 1,700 mm³ during the test period were euthanized from the viewpoint of animal ethic. In this example, the control vaccinia virus, the mIL12-carrying vaccinia virus, or the hIL7-carrying vaccinia virus (each 2×10⁷ PFU/dose, three doses) (respectively referred to as the “control VV treated group”, the “mIL12-carrying VV treated group”, and the “hIL7-carrying VV treated group” in the Table.) was used with the same injection volume (30 μL per dose) and the same dilution solution (PBS) as a virus compared with the mIL12 and hIL7-carrying vaccinia virus (2×10′ PFU/dose, three doses).

As a result, three individuals finally achieved complete remission in the mIL12 and hIL7-carrying vaccinia virus treated group. On the other hand, no individual achieved complete remission in the group receiving the comparison virus (Table 4-1). Thus, the administration of the mIL12 and hIL7-carrying vaccinia virus was shown to have a higher complete remission-inducing effect in comparison with the hIL7-carrying vaccinia virus or the mIL12-carrying vaccinia virus in syngeneic cancer-bearing mouse models.

TABLE 4-1 The number of mice individual that achieved complete remission by administration of mIL12 and hIL7-carrying vaccinia virus Number of mouse individual achieved complete remission/ Number of mouse Experimental group individual examined Vehicle (PBS) treated group 0/12 Control VV treated group 0/12 hIL7-carrying VV treated group 0/12 mIL12-carrying VV treated group 0/12 mIL12 and hIL7-carrying VV treated 3/12 group

(2) A Mixture of mIL12-Carrying Vaccinia Virus and hIL7-Carrying Vaccinia Virus

The complete remission-inducing effect of a 1:1 mixture of the mIL12-carrying vaccinia virus and the hIL7-carrying vaccinia virus (hereinafter, referred to as the “mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus”) in vivo was evaluated using syngeneic cancer-bearing mice.

Experiment was conducted in the same way as (1), with the proviso that the murine lung cancer cell LLC1 suspended at 8×10⁶ cells/mL was transplanted. Furthermore, instead of 30 μL (2×10⁷ PFU) of the mIL12 and hIL7-carrying vaccinia virus diluted to a concentration of 6.7×10⁸ PFU/mL, 30 μL (each 2×10⁷ PFU/dose, three doses) of the mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus (each virus was diluted to 6.7×10⁸ PFU/mL in PBS) (referred to as the “treatment group of mixture of mIL12-carrying VV and hIL7-carrying VV” in the Table.) was used. Seven mice (n=7) were used. The control vaccinia virus (4×10⁷ PFU/dose, three doses), the 1:1 mixture of the mIL12-carrying vaccinia virus and the control vaccinia virus (each 2×10⁷ PFU/dose, three doses), or the 1:1 mixture of the hIL7-carrying vaccinia virus and the control vaccinia virus (each 2×10⁷ PFU/dose, three doses) (respectively, referred to as the “control VV treated group”, the “treatment group of mixture of mIL12-carrying VV and control VV”, and the “treatment group of mixture of hIL7-carrying VV and control VV” in the Table.) was used with an injection volume of 30 μL each as a comparison virus.

As a result, four individuals in the group receiving the mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus achieved complete remission. Only one individual achieved complete remission in the group receiving the mixture of mIL12-carrying vaccinia virus and the control vaccinia virus, while no individual achieved complete remission in the groups receiving other comparison viruses (Table 4-2). Thus, the mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus was shown to have higher complete remission-inducing effect in comparison with mixtures containing either of the hIL7-carrying vaccinia virus or the mIL12-carrying vaccinia virus in a syngeneic cancer-bearing mouse model.

TABLE 4-2 The number of mice individual that achieved complete remission by administration of the mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus Number of mouse individual achieved complete remission/ Number of mouse Experimental group individual examined Vehicle (PBS) treated group 0/7 Control VV treated group 0/7 Treatment group of mixture of hIL7-carrying 0/7 VV and control VV Treatment group of mixture of mIL12-carrying 1/7 VV and control VV Treatment group of mixture of mIL12-carrying 4/7 VV and hIL7-carrying VV

Example 8: Acquired Immunity Effect of Genetically Engineered Vaccinia Virus in Syngeneic Cancer-Bearing Mouse Models (Tumor-Rejecting Effect by Acquired Immunity)

(1) mIL12 and hIL7-Carrying Vaccinia Virus:

To the mice achieved complete remission as a result of treating with the mIL12 and hIL7-carrying vaccinia virus, the rechallenge experiment of the same cancer cells was conducted to evaluate acquired immunity effect of the virus.

Specifically, LLC1 cancer-bearing mice were first generated according to Example 7, and the mIL12 and hIL7-carrying vaccinia virus was intratumorally administered in the mice (with the proviso that the intratumoral injection of the virus was also conducted on 1st and 3rd days after the first administration in addition to 2nd and 4th days (total 5 times); referred to as the “mIL2 and hIL7-carrying VV treated group” in the Table.). The complete remission was confirmed on 23th day after the last administration of the virus. Into the individuals that still maintain the complete remission state on 51th day after the last administration and age-matched mice not inoculated with virus (control group), 50 μL of LLC1 cancer cells suspended at 8×10⁶/mL in PBS was subcutaneously transplanted. The tumor volume was calculated according to Example 6 and the number of individuals that were recognized to have tumor formation by visual observation and palpation on 14th day after the LLC1 transplantation was counted to determine the ratio of the number of mouse individuals having engrafted tumor/the number of mouse individuals in which cancer cells were transplanted. In this Example, the control group and the virus treated group were tested by the Fisher's exact test and the acquired immunity effect was evaluated to be positive when there was a significant difference (less than 5%).

As a result, subcutaneous tumor was formed in the all cases of 10 individuals in the total 10 individuals in the control group, but 6 individuals in the total 10 individuals in the mIL12 and hIL7-carrying virus treated group had no tumor formation of rechallenged LLC1 cancer cells found in the visual observation and palpation (Table 5-1) (P<0.05, Fisher's exact test). Thus, the acquired immunity effect of the administration of the mIL12 and hIL7-carrying vaccinia virus was confirmed in this Example.

TABLE 5-1 Result of cancer cell rechallenge test in mice achieved complete remission Number of mouse individual having engrafted tumor/ Number of mouse individual in which cancer cells were Experimental group transplanted Control group 10/10 mIL12 and hIL7-carrying VV treated group  4/10

(2) Mixture of mIL12-Carrying Vaccinia Virus and hIL7-Carrying Vaccinia Virus:

To the mice achieved complete remission as a result of treating with the mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus, the rechallenge experiment of the same cancer cells was conducted to evaluate acquired immunity effect of the virus.

Specifically, the experiment was conducted in the same way as in (1). However, instead of the mice achieved complete remission by the administration of the mIL12 and hIL7-carrying vaccinia virus, the mice achieved complete remission by the administration of the mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus according to Example 7 (2) (1st, 3rd, and 5th day after the group assignment, total 3 times) were used (referred to as the “treatment group of mixture of mIL12-carrying VV and hIL7-carrying VV” in the Table.). The further transplantation of the cancer cells was conducted on 74th day after the last administration of the viruses (determination of complete remission was made on 24th day after the last administration).

As a result, subcutaneous tumor was formed in the all individuals in the total eight individuals in the control group on 14th day after further transplantation of the cancer cells, but eight individuals in the total 10 individuals in the treatment group of mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus had no tumor formation of rechallenged LLC1 cancer cells found in the visual observation and palpation (Table 5-2) (P<0.05, Fisher's exact test).

Thus, the acquired immunity effect of the administration of the mixture of mIL12-carrying vaccinia virus and hIL7-carrying vaccinia virus was confirmed in this Example.

TABLE 5-2 Result of cancer cell rechallenge test in mice achieved complete remission Number of mouse individual having engrafted tumor/ Number of mouse individual in which cancer cells were Experimental group transplanted Control group 8/8  Treatment group of mixture of mIL12- 2/10 carrying VV and hIL7-carrying VV

Example 9: Construction of Transfer Vector Plasmid DNA

Transfer vector plasmid DNAs to be used for generating recombinant vaccinia viruses by homologous recombination were prepared as follows.

(1) Construction of pUC19-VGF Transfer Vector Plasmid DNA

The pUC19-VGF vector was prepared according to WO 2015/076422. More specifically, genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as template and the pUC19 vector (product code: 54357) from Invitrogen was used for the preparation of the pUC190VGF vector.

(2) Construction of pTN-VGF-SP-Luc2 Transfer Vector Plasmid DNA

A BFP gene region was amplified with two primers (SEQ ID NO: 30 and SEQ ID NO: 31) using DNA of the pTagBFP-N vector (FP172, Evrogen) as template. The PCR product was digested with the restriction enzymes SfiI and EcoRI and cloned into the same restriction enzyme sites in the pTK-SP-LG vector (WO 2015/076422 with the proviso that genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as template and the pUC19 vector (product cord: 54357) from Invitrogen was used; and, for the pVNC 110-Luc/IRES/EGFP plasmid, pVNC110-Luc/IRES/EGFP described in WO 2011/125469 was used.) to construct pTK-SP-BFP in which BFP is linked to a synthetic vaccinia virus promoter (Hammond et al. (1997) Journal of Virological Methods 66: 135-138). Next, pTK-SP-BFP was digested with the restriction enzymes SphI and EcoRI and the ends were blunted. The resulting DNA fragment was cloned into the pUC19-VGF vector at a site generated by digesting with the restriction enzyme AccI and blunting the ends to construct pTN-VGF-SP-BFP. Next, a polynucleotide fragment (100 to 1752 in Accession No. DQ188840) encoding the luciferase Luc2 gene was cloned into pTN-VGF-SP BFP for replacement of BFP to construct a transfer vector plasmid DNA having a Luc2 gene actuated by a synthetic vaccinia virus promoter. The constructed plasmid DNA was named pTN-VGF-SP-Luc2.

(3) Construction of pTN-O1L-SP-BFP and pTN-O1L-SP-Lac Transfer Vector Plasmid DNAs

In the same way as (2) above, pTK-SP-BFP was digested with the restriction enzymes SphI and EcoRI and the DNA fragment obtained by blunting the ends was cloned into the pUC19-O1L vector (WO 2015/076422 with the proviso that genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as a genomic DNA of the strain LC16mO and the pUC19 vector (product cord: 54357) from Invitrogen was used as a pUC19 vector; and; the O1L gene region was inserted into the XbaI site in the pUC19 vector) at a site generated by digesting the plasmid with the restriction enzyme XbaI and blunting the ends to prepare the transfer vector plasmid DNA. The prepared plasmid DNA was named pTN-O1L-SP-BFP. Next, a polynucleotide containing the Escherichia coli LacZ gene with codons optimized for human (SEQ ID NO: 32) was digested with the restriction enzymes AgeI and NheI. The polynucleotide fragment encoding LacZ was cloned into the same restriction enzyme sites (the AgeI and NheI sites) in the pTN-O1L-SP-BFP vector for replacement of BFP to construct a transfer vector plasmid DNA having a LacZ gene actuated by a synthetic vaccinia virus promoter. The constructed plasmid DNA was named pTN-O1L-SP-LacZ.

(4) Construction of pTN-DsRed (B5R-) and pTN-B5RΔ1-4 Transfer Vector Plasmid DNAs

The B4R gene region was amplified with two primers (SEQ ID NO: 26 and SEQ ID NO: 27) using DNA of pB5R (WO 2011/125469, with the proviso that genomic DNA (Accession No. AY678277.1) of the strain LC16mO was used as template) as template. Moreover, the DsRed gene region was amplified with two primers (SEQ ID NO: 28 and SEQ ID NO: 29) using DNA of pDsRed-Express-N1 (Clontech) as template. The former PCR product was digested with the restriction enzymes NotI and FspI and the latter PCR product was digested with the restriction enzymes FspI and MfeI. These two DNA fragments were cloned into pB5R digested with the restriction enzymes NotI and MfeI to prepare a transfer vector plasmid DNA. The prepared plasmid DNA was named pTN-DsRed (B5R-). Meanwhile, pB5R was digested with the restriction enzymes NotI and NspI or the restriction enzymes NspI and SacI. These DNA fragments (The former corresponds to a region including 236 to 317 (C-terminal) and further B6R. The latter corresponds to a region including B4R and 1 to 21 of B5R (N-terminal). The protruding end (corresponding to a sequence of 236 to 237) in the region of the former and the protruding end (corresponding to a sequence of 20 to 21) in the region of the latter are complementary to each other.) were cloned into pB5R digested with the restriction enzymes NotI and MfeI to construct a transfer vector plasmid DNA. The constructed plasmid DNA was named pTN-B5RΔ1-4. The pTN-B5RΔ1-4 encodes the B5R with the deletion of four SCR domains. The amino acid sequence of the B5R protein with the deletion of four SCR domains is the sequence set forth in SEQ ID NO: 25.

Example 10: Construction of Genetically Engineered Vaccinia Virus

A recombinant vaccinia virus (referred to as LC16mO VGF-SP-LucGFP/olL-p7.5-DsRed) deficient in the functions of VFG and O1L was prepared from the vaccinia virus strain LC16mO. This recombinant vaccinia virus was sequenced with a next-generation sequencer PacBio RSII (Pacific Bioscience) and the virus genome was reconstituted from the obtained sequence information using the Sprai (Miyamoto et al. (2014) BMC Genomics 15:699 (1-8)) software to determine the nucleotide sequence, which was the nucleotide sequence set forth in SEQ ID NO: 41. Moreover, loop sequences were added to both ends of the nucleotide sequence and the loop sequences at both ends were the nucleotide sequences set forth in SEQ ID NO: 39 or 40.

(1) The recombinant vaccinia viruses having the virus genome illustrated in FIG. 6A were collected. The virus collecting procedure is specifically described below. CV1 cells (ATCC® CCL-70) or RK13 cells (ATCC® CCL-37) cultured to 80% confluent in 6-well dishes were infected with LC16mO VGF-SP-LucGFP/O1L-p7.5-DsRed at a MOI (Multiplicity of infection) of 0.02 to 0.1 and the virus was allowed to be adsorbed at room temperature for 1 hour. pTN-O1L-SP-BFP constructed in Example 9 (3) was mixed with FuGENE® HD Transfection Reagent (Roche), added to cells according to the manual to be incorporated into the cells and the cells were cultured in the presence of 5% CO₂ at 37° C. for 2-5 days. Infected cells were detached by a scraper and collected with a culture solution. The cells were freeze-thawed, sonicated, and diluted with Opti-MEM (Invitrogen) so as to obtain single plaques by the following operation. 100 μL of the obtained diluted fluid was added to inoculate BS-C-1 cells (ATCC® CCL-26) or RK13 cells cultured to sub-confluent in 6-well dishes. 2 mL of the Eagle MEM medium (NISSUI, 05900) containing 0.8% methylcellulose (Wako Pure Chemical Industries, Ltd., 136-02155), 5% fetal bovine serum, 0.225% sodium bicarbonate (Wako Pure Chemical Industries, Ltd., 195-16411), and GlutaMAX Supplement I (GIBCO, 35050-061) was added and the cells were cultured in the presence of 5% CO₂ at 37° C. for 2-5 days. The medium was removed and plaques, as indicated by the BFP expression, were scraped off with the pointing end of a tip to be suspended into Opti-MEM. This operation was repeated three times or more with BS-C-1 or RK13 cells to purify plaques and collect the recombinant virus plaques (In this Example, the procedure up to this point is hereinafter referred to as the “virus collecting.”). The collected plaques were suspended into Opti-MEM and sonicated. Genomic DNA was extracted from 200 μL of the sonicated solution using High Pure Viral Nucleic Acid Kit (Roche) according to the manual and screened by PCR. PCR was performed with the two primers (SEQ ID NO: 33 and SEQ ID NO: 34) for VGF, with the two primers (SEQ ID NO: 35 and SEQ ID NO: 36) for O1L, with the two primers (SEQ ID NO: 37 and SEQ ID: NO 38) for B5R. Among the clones from which an expected size of PCR product was detected, a virus clone for which the correct nucleotide sequence of the PCR product was confirmed by direct sequencing (referred to as LC16mO VGF-SP-LucGFP/O1-SP-BFP or B5R virus; in the figure, also referred to simply as B5R; in FIG. 6A) was selected and proliferated with A549 (ATCC® CCL-185) or RK13 cells and then the virus titer was measured with RK13 cells; and the clone was used for the experiments described in Examples A4 to AS7. Using LC16mO VGF-SP—LucGFP/O1-SP-BFP and pTN-DsRed (B5R-) prepared in Example 9 (4), the recombinant virus, as indicated by the DsRed expression instead of the BFP expression, was collected in the same way as described above. The collected virus was named LC16mO Δ-DsRed VGF-SP-LucGFP/O1L-SP-BFP.

(2) A recombinant virus having the deletion of the 4 SCR domains in the B5R protein shown in FIG. 6B was collected. Specifically, using LC16mO Δ-DsRed VGF-SP-LucGFP/O1L-SP-BFP prepared in Example 10 (1) and pTN-B5RΔ1-4 constructed in Example 9 (4), the recombinant virus, as indicated by the disappearance of DsRed expression instead of the BFP expression, was collected in the same way as that in Example 10 (1). The collected laue was screened by PCR according to the same procedure as described in Example 10 (1) and the PCR product was confirmed by direct sequencing. A virus clone having the correct nucleotide sequence (referred to as LC16mO ΔSCR VGF-SP-LucGFP/O1-SP-BFP or ΔSCR virus; in the figure, referred to simply as ΔSCR (FIG. 6B)) was selected and proliferated with A549 (ATCC® CCL-185) or RK13 cells, and then the virus titer was measured with RK13 cells; and the clone was used for the experiments described in Examples 12 to 15.

(3) To prepare the B5R virus and the ΔSCR virus, in which a polynucleotide encoding LucGFP in the VGF gene and a polynucleotide encoding BFP in the O1L gene are replaced with a polynucleotide encoding Luc2 and a polynucleotide encoding LacZ, respectively, the B5R virus collected in Example 10 (1) or ΔSCR virus collected in Example 10 (2), pTN-VGF-SP-Luc2 prepared in Example 9 (2) and pTN-O1L-SP-LacZ prepared in Example 9 (3) were used and recombinant viruses were collected according to the same method as in Example 10 (1) (note that CV-1 cells were used as cells). The recombinant virus originating from the B5R virus was named B5R-LL virus and the recombinant virus originating from the ΔSCR virus was named ΔSCR-LL virus.

Example 11. Collection and Titer Measurement of EEV or IMV

EEV has the property of being released in a cell supernatant at the time of initial infection while IMV has the property of staying inside cells at the time of initial infection; and thus, viruses in a supernatant of a culture solution of virus-infected cells were collected as EEV. That is, the culture solution was collected after 48 hours post-infection; suspension cells were precipitated by centrifugation (700×g, 4° C., 10 minutes); only a supernatant was isolated and collected as EEV; and the titer measurement was conducted. Meanwhile, together with the remaining suspension cells after the collection of the supernatant, adherent cells in a plate were washed with Dulbecco phosphate-buffered saline (D-phosphate buffered saline; D-PBS (Wako); detached by a cell scraper; collected by addition of Opti-MEM; freeze-thawed, and sonicated, so that the cells were crushed; and after centrifugation (700×g, 4° C., 10 minutes), a supernatant was collected as IMV.

For virus titer measurement, RK13 cells that were inoculated to almost confluent in 6 well plates were infected with serial dilutions of each virus of EEV or IMV (10¹ to 10⁷-fold dilutions; dilution ratios were varied depending on an assumed virus titer); 2 mL of the Eagle MEM medium (NISSUI, 05900) containing 0.8% methylcellulose (Wako Pure Chemical Industries, Ltd., 136-02155), 5% fetal bovine serum, 0.225% sodium bicarbonate (Wako Pure Chemical Industries, Ltd., 195-16411), and GlutaMAX Supplement I (GIBCO, 35050-061) was added and the cells were cultured in the presence of 5% CO₂ at 37° C. for 3 days; and then, the number of formed virus plaques was measured and the virus titer (production) of EEV or IMV was calculated thereby.

Example 12. Cell Killing Effect of EEV or IMV of Recombinant Vaccinia Virus Having a Gene Encoding B5R with the Deletion of SCR Domains 1 to 4

Influence on the cell killing effect of EEV or IMV was identified.

(1) Cell Killing Effect of IMV

First, for comparison on the cell killing effect of IMV, 4 kinds of ovarian cancer cell strains (A2780 (ECACC 93112519), CaOV3 (ATCC® HTB-75), RMG-1 (JCRB JCRB0172), and SKOV3 (ATCC® HTB-77)) were inoculated at a concentration of 6.0×10³ cells/well and cultured 37° C. for 24 hours; then, at 60 to 80% confluency, each cell line was infected with B5R virus or ΔSCR virus at MOI of 0, 0.001, 0.01, 0.1 and 1. It was thought that B5R virus or ΔSCR virus entirely had an IMV form. After 20 hours post-infection, the florescence observation (FIG. 7A) and the cell viability assay (Panel A of FIG. 8) were conducted by use of BZ-X700 (Keyence) and Cell Titer 96 Aqueous Nonradioactive Cell Proliferation Assay (Promega), respectively. In a fluorescence observation image, virus proliferation was observed as GFP fluorescence by the expression of an EGFP gene inserted into a VGF gene of viruses. Cell viabilities were calculated by taking a value for a well with no cells inoculated as 0% viability and a value for a well with cells inoculated but no viruses added as 100% viability.

(2) Cell Killing Effect of EEV

Next, for comparison on the cell killing effect of EEV, the same cells described in the above (1) were infected with each virus at MOI of 0, 0.001, 0.01, 0.1 and 1, and cultured for 48 hours. Thereafter, 50 μl of culture solution of infected cells was collected and only a supernatant was collected as EEV by centrifugation (700×g, 4° C., 10 minutes). The 4 kinds of ovarian cancer cell strains newly inoculated in 96-well plates were infected with the collected EEV. After 120 hours post-infection with EEV, the fluorescence observation (FIG. 7B) and the cell viability assay (Panel B of FIG. 8) were conducted in the same manner as in the above (1).

As indicated in FIG. 7A and Panel A of FIG. 8, it was found that the virus proliferation and the cell viability almost agreed with each other, and a large difference between B5R virus and ΔSCR virus was not found in terms of the proliferation range and the cell viability at the time of IMV infection in all cells (FIG. 7A, Panel A of FIG. 8). It was considered that this was because the amount of EEV was about 1% of the amount of IMV or lower than that and the effects observed were attributed mainly to IMV; and, it was considered that there was no difference in all cells in terms of the production of IMV. Meanwhile, as indicated in FIG. 7B and Panel B of FIG. 8, it was found that ΔSCR virus had an increased proliferation range and a decreased cell viability in comparison with B5R virus in A2780 and CaOV3 cells at the time of EEV infection, and there were no differences in the proliferation range and the cell viability in RMG-1 and SKOV3 cells. (FIG. 7B, Panel B of FIG. 8).

Example 13: Immune Evasion of EEV Derived from Recombinant Vaccinia Virus Having a Gene Encoding B5R Having the Deletion of SCR Domains 1 to 4

Next, an increase of immune evasion ability of viruses by the deletion of a region encoding an SCR domain was verified by neutralization experiments of viruses. EEV is neutralized by CDC activity of anti-B5R antibodies and complements (Benhnia et al. (2009) Journal of Virology 83(3): 1201-1215), and thus, virus neutralization was conducted by addition of rabbit-derived anti-vaccinia virus serums and rabbit complements were added to EEV and IMV.

(1) Virus Neutralization Treatment

Specifically, for the production of EEV and IMV, as virus-producing/infected cells, SKOV3 cells were used for EEV and IMV both, since they exhibited no difference in the production amount between B5R virus/ΔSCR virus. SKOV3 cells were inoculated in a 24-well plate at 5.0×10⁴ cell/well, and cultured for 24 hours; then, at 60 to 80% confluency, they were infected with B5R virus or ΔSCR virus at MOI of 0.1. After infection, EEV and IMV were collected by the method described in the above Example 11 at the time of 48 hours after the infection. 10 μl of EEV (about 1500 to 2000 PFU) or 1 μl of IMV (about 5000 to 7000 PFU) derived the collected B5R virus or ΔSCR virus, respectively was mixed in Opti-MEM with 0, 0.2, 0.5 or 1% rabbit anti-vaccinia virus serum (Capricorn, IgG fraction, ELISA antibody titer 1:1000, anti-B5R antibodies were detected by ELISA; in FIGS. 9 to 10, referred to as anti VV serum or simply serum) and 0, 1, 3, 10 or 25% rabbit complement (Cedarlane Laboratories; hereinafter and in FIGS. 9 to 10, referred to simply as complement), and, in total, 50 μl of virus mixture was obtained and reacted at 37° C. for 30 minutes. Next, SKOV3 cells, which was inoculated in a 96-well plate at 6.0×10³ on the previous day, were infected with the virus mixture, and the virus was adsorbed at 37° C. for 2 hours. After 2-hour adsorption, the virus mixture was removed, and RPMI-1640 medium (Wako) containing 10% fetal bovine serum was added as a new culture solution and cultured at 37° C. for 96 hours.

(2) Fluorescence Observation Image after Neutralization Treatment

After 96-hour culture, fluorescence observation was conducted on vaccinia viruses proliferated in infected cells according to the method described in Example 12. FIG. 9 shows fluorescence observation results at the time of 96-hour post-infection. A region wherein green is confirmed in fluorescence observation indicates proliferated viruses.

As indicated in FIG. 9, it was confirmed that B5R virus-derived EEV was efficiently neutralized by mixing with antibodies and complements in view of infection images after virus neutralization treatment on EEV while ΔSCR virus-derived EEV can evade neutralization with antibodies and complements and proliferate (Panel A of FIG. 9). Also, it was confirmed that in view of infection images after virus neutralization treatment on IMV, it was confirmed that both B5R virus and ΔSCR virus were efficiently neutralized with antibodies and complements (Panel B of FIG. 9). These results were in agreement with the existing report that IMV did not have resistance to the immunity and EEV had immune evasion ability; and further, it is also in agreement with the fact that ΔSCR virus evades the identification by anti-B5R antibodies.

(3) Neutralization Evasion Ability

FIG. 10 shows results obtained by converting fluorescence observation results from FIG. 9 into numbers (hereinafter, referred to “hybrid count”). A higher value for hybrid count indicates a higher neutralization evasion ability. ΔSCR virus-derived EEV tends to indicate a higher neutralization evasion ability compared to B5R virus-derived EEV (Panel A of FIG. 10). Meanwhile, regarding IMV, no large difference was found between those derived from ΔSCR virus and those derived from B5R virus (Panel B of FIG. 10).

In view of the above, it was suggested that ΔSCR virus-derived EEV had an improved immune evasion ability compared to B5R virus-derived EEV.

Example 14: In Vivo Immune Evasion Ability and Antitumor Effect of Recombinant Vaccinia Virus-Derived EEV Having a Gene Encoding B5R Having the Deletion of SCR Domains 1 to 4

Improvements of immune evasion ability and antitumor effect on recombinant vaccinia virus having a gene encoding B5R having the deletion of SCR domains 1 to 4 were verified by preclinical study using mice.

(1) Verification Procedure

Specifically, human ovarian cancer A2780 cells (5×10⁶ cells), which constitutively express Renilla luciferase neomycin-resistant fusion gene (Renilla Luciferase-neo: hereafter, sometimes referred to as “Rluc”) of pmirGLO Vector (Promega), were intraperitoneally transplanted into BALB/c-nu/nu mice, and proliferated for 10 days. Next, A2780 cells for EEV production were inoculated into a T-25 flask at 1.35×10⁶; after 24-hour culture, the cells were infected with B5R virus or ΔSCR virus at MOI of 0.05; after 48-hour culture, the collected culture solution was centrifuged (700×g, 4° C., 5 minutes); and a supernatant was collected as EEV. Before EEV administration, 100 μl of rabbit anti-vaccinia virus serum (Capricorn, IgG fraction; hereinafter and in FIGS. 12 to 13, referred to simply as serum; in FIGS. 11A and 11B, referred to as anti VV serum) was intraperitoneally administered into nu/nu mice to create a spurious immune environment. 500 μl of the collected EEV (B5R virus: about 1.2×10⁵ PFU, A SCR virus: about 7×10⁵ PFU) was administered. Administration of Vivo Glo Luciferin (Promega) enabled noninvasive detection of Fluc luminance of viruses (virus proliferation), and administration of ViviRen In Vivo Renilla Luciferase Substrate (Promega) enabled noninvasive of Rluc luminance of transplanted A2780 cells (tumor growth) by use of an in vivo imaging system (Berthold, NightDHADE LB985).

FIG. 11A shows detection results of virus Fluc luminance (that is, biodistribution of viruses) on 3 days (Day 3) and 7 days (Day 7) after the EEV administration; and FIG. 11B shows detection results of tumor Rluc luminance on 3 days before the EEV administration (Day −3) and 8 days after the administration (Day 8). In FIGS. 11A and 11B, results from the bottom are for control group (phosphate buffered saline (PBS) was administered instead of EEV), B5R virus-EEV treated group, and ΔSCR virus-EEV treated group.

(2) Virus Proliferation and Tumor Growth

As shown in FIG. 11A (detection results of virus Fluc luminance), on 3 days after the EEV administration, B5R virus-EEV+serum treated mice and ΔSCR virus-EEV+serum treated mice both suppressed virus proliferation, but on 7 days after the EEV administration, strong virus proliferation in the peritoneal cavity was found in almost all individuals of the ΔSCR virus-EEV+serum treated mice. In contrast, B5R virus-EEV+serum treated mice suppressed the virus proliferation.

As indicated in FIG. 11B (detection results of tumor Rluc), for serum non-treated group on 8 days after the EEV administration, administration of either of B5R virus-EEV and ΔSCR virus-EEV resulted a large decrease of tumor growth in comparison with 3 days before the EEV administration. Meanwhile, among B5R virus-EEV+serum treated mice, only one mouse decreased tumor growth after the EEV administration while 4 mice of ΔSCR virus-EEV+serum treated mice decreased tumor growth after the administration.

Panel A of FIG. 12 shows detected values of virus Fluc luminance up to 10th day after the EEV administration; Panel B of FIG. 12 shows detected values of tumor Rluc luminance from before the EEV administration up to 15th day after the EEV administration.

As indicated in Panel A of FIG. 12 (detected values of virus Fluc luminance), the serum non-treated groups reached a peak on 5th day after each EEV administration while ΔSCR virus-EEV; serum treated mice and B5R virus-EEV+serum treated mice reached a peak 7 days and 10 days, respectively, after the administration. In FIG. 12, ΔSCR virus was expressed as “delSCR.” “Back” indicates Fluc luminance of the background with no mouse.

As indicated in Panel B of FIG. 12 (detected values of tumor Rluc luminance), among serum non-treated groups, either of B5R virus-EEV and ΔSCR virus-EEV almost eliminated tumor on 8th day after each EEV administration. On the other hand, ΔSCR virus-EEV+serum treated mice eliminated tumor on 11th day after the EEV administration, and B5R virus-EEV+serum treated mice had remaining tumor even on 15th day after the EEV administration. “Back” indicates Rluc luminance of the background with no mouse.

(3) Mouse Viability

FIG. 13 shows a survival rate of each mouse after the EEV administration. As shown in FIG. 13, all of the EEV administration groups exhibited a survival extension compared to Mock (PBS, PBS+serum) groups, but an early survival rate decrease was identified in B5R virus-EEV+serum treated mice. Meanwhile, ΔSCR virus-EEV+serum treated mice exhibited a median value for survival extension equivalent to that of the serum non-treated group (ΔSCR virus-EEV+serum treated mice had a median value of 77 while serum non-treated group (ΔSCR virus-EEV) had a median value of 74.5); and they had a significant difference confirmed by Log-rank test in comparison with B5R virus-EEV+serum treated mice (P=030291).

In this way, B5R virus is remarkably different from ΔSCR virus in terms of the antitumor effect in the presence of serum (that is, immune state); and it was proved that ΔSCR virus enhanced antitumor effect against tumor cells in the mouse body under the immune environment.

Example 15: In Vivo Antitumor Effect of Recombinant Vaccinia Virus Having a Gene Encoding B5R Having the Deletion of SCR Domains 1 to 4

Antitumor effect by SCR deletion was verified in isograft models for the immunoresponsiveness.

(1) Purification of Recombinant Virus

For purification, A548 cells or RK13 cells were infected with B5R-LL virus and ΔSCR-LL virus prepared in Example 10 (3) and cultured in the presence of 5% CO₂ at 37° C. for 2 to 5 days; and infected cells were collected. The cells were freeze-thawed, sonicated, or treated with Benzonase. Using OptiPrep (Axis Shield), purification was conducted by density gradient centrifugation. Thereafter, the virus titer of each virus was measured with RK13 cells, and used for the experiment described below in (2).

(2) Tumor Volume and Virus Growth

As the isograft model, murine colon cancer CT25 cells were subcutaneously transplanted in the left and right abdomens of BALBc/AJjcl mice at 5×10⁵. The mice were grown for 7 days until each group had an average value for a tumor volume with tumor diameters measured by a caliper (minor axis mm×minor axis mm×major axis mm×0.5) of 48 to 88 mm³ at the virus treated side (left side) and 12 to 115 mm³ at the virus non-treated side (right side). After tumor growth, B5R-LL viruses or ΔSCR virus-LL viruses were directly administered to the tumor transplanted in the murine left abdomen at 5×10⁷ PFU. A group having PBS (35 μL) intratumorally administered instead of each virus was also prepared (each group: N=5). Administration was conducted every other day on Day 0, 2 and 4, in total 3 times. Tumor diameters were measured by a caliper until 20 days after the initial administration, and changes of tumor volumes were observed. Further, until 7 days after the initial administration, Vivo Glo Luciferin (Promega) was administered and the progress of virus proliferation was observed with Fluc luminance of viruses.

Consequently, as indicated in the upper graph of FIG. 14, it was confirmed by Two-way ANOVA statistical analysis (P<0.005) that the tumor at the virus treated side (left side) was significantly suppressed on 17th and 20th days after the initial administration of viruses with B5R-LL viruses and ΔSCR-LL viruses compared to PBS administration of Mock (the upper graph of FIG. 14). Further, complete remission was found in two of five ΔSCR-LL treated mice; however, complete remission was achieved by none of B5R-LL mice. In addition, regarding the virus non-treated side (right side) tumor, B5R-LL virus treated mice and ΔSCR-LL virus treated mice significantly suppressed tumor growth compared to the PBS treated group (the lower graph of FIG. 14). In particular, it was confirmed by Two-way ANOVA statistical analysis (P<0.01) that on 20th day, ΔSCR-LL virus treated mice significantly suppressed their tumor volumes compared to B5R-LL virus treated mice.

Moreover, the progress of virus proliferation was observed by luminance detection of Fluc incorporated into viruses. No virus was confirmed at any time within the observation period (7 days) in the tumor at the virus non-treated side. Further, in the tumor at the virus treated side, there was a tendency that B5R-LL viruses proliferated more than ΔSCR-LL viruses (FIG. 15). Both of the viruses reached a peak on Day 3 after the second administration, and were almost eliminated on Day 7 after the third administration. In contrast, the antitumor effect of viruses was prominent on 7th day and thereafter. That is, it was found that the tumor growth inhibition action initiated by SCR deletion was not in direct correlation with the virus amount, and was demonstrated eve in tumor with no virus detected (virus non-treated tumor) or even after viruses were already eliminated.

The above suggested that the antitumor effect by SCR deletion involved not only an antitumor action of viruses by themselves but also an antitumor action of a living body initiated by viruses. It was considered that the antitumor action of a living body was caused by the activation of antitumor immunity, for example. That is, it was thought that ΔSCR suppressed the elimination by the immunity of vaccinia virus, and on top of that, it activated the immunoreaction against cancer cells.

SEQUENCE LISTING

Included with the application filed herewith is a Sequence Listing, which is incorporated by reference in its entirety and forms part of the present application. A summary of the sequences presented is as follows. The nucleotide sequences set forth in SEQ ID NOs: 1-6 and 10-15 are primers. The nucleotide sequences set forth in SEQ ID NOs: 7, 8, and 9 are a polynucleotide containing the human IL-12 gene, a polynucleotide containing the human IL-7 gene, and a polynucleotide containing the Escherichia coli LacZ gene, respectively. In SEQ ID NO: 7, the nucleotide sequence of 14-1000 corresponds to the region encoding the p40 subunit of IL-12 and the nucleotide sequence of 1606-2367 corresponds to the region encoding the subunit a of IL-12. The nucleotide sequences set forth in SEQ ID NOs: 16 and 17 are the restriction enzyme sites linked to each of the gene coding regions of SEQ ID NOs: 7-9. The amino acid sequence set forth in SEQ ID NO: 18 is a B5R protein having the deletion of the 4 SCR domains. The nucleotide sequences set forth in SEQ ID NOs: 19 and 20 are the sequences of loop sequences at both ends in LC16mO VGF-SP-LucGFP/O1L-p7.5-DsRed. The nucleotide sequence set forth in SEQ ID NO: 21 is the sequence except the loop sequences at both ends in LC16mO VGF-SP-LucGFP/O1L-p7.5-DsRed. The nucleotide sequence set forth in SEQ ID NO: 22 is a DNA fragment containing the p7.5k promoter and the DsRed fragment. The nucleotide sequence set forth in SEQ ID NO: 23 is a polynucleotide containing the murine IL-12 gene. The amino acid sequence set forth in SEQ ID NO: 24 is an amino acid sequence from 22 to 237 amino acids in the amino acid sequence registered under the Accession No. AAA48316.1. The amino acid sequence set forth in SEQ ID NO: 25 is a B5R protein having the deletion of the 4 SCR domains. The nucleotide sequences set forth in SEQ ID NOs: 26 to 31 and 33 to 38 are primers. The nucleotide sequence set forth in SEQ ID NO: 32 is a polynucleotide containing the Escherichia coli LacZ gene with optimized codons. The nucleotide sequence set forth in SEQ ID NO: 39 is a loop sequence at an end in LC16mO VGF-SP-LucGFP/O1L-p7.5-DsRed. The nucleotide sequence set forth in SEQ ID NO: 40 is a loop sequence at an end in LC16mO VGF—SP-LucGFP/O1L-p7.5-DsRed. The nucleotide sequence set forth in SEQ ID NO: 41 is a sequence except a loop sequence at an end in LC16mO VGF-SP-LucGFP/O1L-p7.5-DsRed. 

1. A vaccinia virus lacking functions of vaccinia virus growth factor (VGF) and O1L and having a gene encoding B5R in which an SCR (short consensus repeat) domain has been deleted.
 2. The vaccinia virus according to claim 1, wherein the vaccinia virus has a gene encoding B5R in which SCR domains 1 to 4 have been deleted.
 3. The vaccinia virus according to claim 2, wherein the deletion of SCR domains 1 to 4 in B5R is deletion of a region corresponding to the amino acid sequence represented by SEQ ID NO: 24 in B5R.
 4. The vaccinia virus according to claim 1, wherein the gene encoding B5R in which an SCR domain has been deleted is a gene encoding a polypeptide comprising a signal peptide, a stalk, a transmembrane domain and a cytoplasmic tail of B5R.
 5. The vaccinia virus according to claim 1, wherein the B5R in which an SCR domain has been deleted consists of an amino acid sequence of B5R corresponding to the amino acid sequence of SEQ ID NO:
 25. 6. The vaccinia virus according to claim 1, wherein the vaccinia virus is an LC16mO strain.
 7. A pharmaceutical composition comprising a vaccinia virus according to claim 1 and a pharmaceutically acceptable excipient.
 8. The pharmaceutical composition according to claim 7, wherein the pharmaceutical composition is for prevention or treatment of a cancer.
 9. The vaccinia virus according to claim 2, wherein the gene encoding B5R in which an SCR domain has been deleted is a gene encoding a polypeptide comprising a signal peptide, a stalk, a transmembrane domain and a cytoplasmic tail of B5R.
 10. The vaccinia virus according to claim 2, wherein the B5R in which an SCR domain has been deleted consists of an amino acid sequence of B5R corresponding to the amino acid sequence of SEQ ID NO:
 25. 11. The vaccinia virus according to claim 2, wherein the vaccinia virus is an LC16mO strain.
 12. The pharmaceutical composition comprising a vaccinia virus according to claim 2, and a pharmaceutically acceptable excipient.
 13. The vaccinia virus according to claim 4, wherein the B5R in which an SCR domain has been deleted consists of an amino acid sequence of B5R corresponding to the amino acid sequence of SEQ ID NO:
 25. 14. The vaccinia virus according to claim 4, wherein the vaccinia virus is an LC16mO strain.
 15. A pharmaceutical composition comprising the vaccinia virus according to claim 4, and a pharmaceutically acceptable excipient.
 16. A pharmaceutical composition comprising the vaccinia virus according to claim 6, and a pharmaceutically acceptable excipient.
 17. A method of treating cancer comprising administering the vaccinia virus according to claim 1 to a subject with cancer.
 18. The method according to claim 17, wherein the cancer is selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer, and gastric cancer.
 19. A method of treating cancer comprising administering the vaccinia virus according to claim 6 to a subject with cancer.
 20. The method according to claim 19, wherein the cancer is selected from the group consisting of malignant melanoma, lung adenocarcinoma, lung cancer, small cell lung cancer, lung squamous carcinoma, kidney cancer, bladder cancer, head and neck cancer, breast cancer, esophageal cancer, glioblastoma, neuroblastoma, myeloma, ovarian cancer, colorectal cancer, pancreatic cancer, prostate cancer, hepatocellular carcinoma, mesothelioma, cervical cancer, and gastric cancer. 